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''Tetrabiblos'' () 'four books', also known in
Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...
as ''Apotelesmatiká'' () "Effects", and in
Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...
as ''Quadripartitum'' "Four Parts", is a text on the philosophy and practice of
astrology Astrology is a range of divinatory practices, recognized as pseudoscientific since the 18th century, that claim to discern information about human affairs and terrestrial events by studying the apparent positions of celestial objects. Di ...
, written in the 2nd century AD by the
Alexandria Alexandria ( or ; ar, ٱلْإِسْكَنْدَرِيَّةُ ; grc-gre, Αλεξάνδρεια, Alexándria) is the second largest city in Egypt, and the largest city on the Mediterranean coast. Founded in by Alexander the Great, Alexandri ...
n scholar
Claudius Ptolemy Claudius Ptolemy (; grc-gre, Πτολεμαῖος, ; la, Claudius Ptolemaeus; AD) was a mathematician, astronomer, astrologer, geographer, and music theorist, who wrote about a dozen scientific treatises, three of which were of importa ...
( AD 90– AD 168). Ptolemy's ''
Almagest The ''Almagest'' is a 2nd-century Greek-language mathematical and astronomical treatise on the apparent motions of the stars and planetary paths, written by Claudius Ptolemy ( ). One of the most influential scientific texts in history, it can ...
'' was an authoritative text on
astronomy Astronomy () is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, g ...
for more than a thousand years, and the ''Tetrabiblos'', its companion volume, was equally influential in
astrology Astrology is a range of divinatory practices, recognized as pseudoscientific since the 18th century, that claim to discern information about human affairs and terrestrial events by studying the apparent positions of celestial objects. Di ...
, the study of the effects of astronomical cycles on earthly matters. But whilst the ''Almagest'' as an astronomical authority was superseded by acceptance of the
heliocentric model Heliocentrism (also known as the Heliocentric model) is the astronomical model in which the Earth and planets revolve around the Sun at the center of the universe. Historically, heliocentrism was opposed to geocentrism, which placed the Earth a ...
of the
Solar System The Solar System Capitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar ...
, the ''Tetrabiblos'' remains an important theoretical work for astrology. Besides outlining the techniques of astrological practice, Ptolemy's philosophical defense of the subject as a natural, beneficial study helped secure theological tolerance towards astrology in
Western Europe Western Europe is the western region of Europe. The region's countries and territories vary depending on context. The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the ancient Mediterranean ...
during the
Medieval era In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire a ...
. This allowed Ptolemaic teachings on astrology to be included in universities during the
Renaissance The Renaissance ( , ) , from , with the same meanings. is a period in European history marking the transition from the Middle Ages to modernity and covering the 15th and 16th centuries, characterized by an effort to revive and surpass ide ...
, which brought an associated impact upon medical studies and literary works. The historical importance of the ''Tetrabiblos'' is seen by the many ancient, Medieval and Renaissance commentaries that have been published about it. It was copied, commented on, paraphrased, abridged, and translated into many languages. The latest critical Greek edition, by Wolfgang Hübner, was published by Teubner in 1998.


Overview and influence

Ptolemy Claudius Ptolemy (; grc-gre, Πτολεμαῖος, ; la, Claudius Ptolemaeus; AD) was a mathematician, astronomer, astrologer, geographer, and music theorist, who wrote about a dozen scientific treatises, three of which were of importanc ...
is referred to as "the most famous of Greek astrologers" Tester (1987)
p.57
and "a pro-astrological authority of the highest magnitude".Rutkin, H. Darrel, 'The Use and Abuse of Ptolemy's Tetrabiblos in Renaissance and Early Modern Europe', in Jones (2010) p.135-147. As a source of reference his ''Tetrabiblos'' is described as having "enjoyed almost the authority of a Bible among the astrological writers of a thousand years or more". Compiled in
Alexandria Alexandria ( or ; ar, ٱلْإِسْكَنْدَرِيَّةُ ; grc-gre, Αλεξάνδρεια, Alexándria) is the second largest city in Egypt, and the largest city on the Mediterranean coast. Founded in by Alexander the Great, Alexandri ...
in the 2nd century, the work gathered commentaries about it from its first publication. It was translated into
Arabic Arabic (, ' ; , ' or ) is a Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C. E.Watson; Walter ...
in the 9th century, and is described as "by far the most influential source of medieval Islamic astrology". With the translation of the ''Tetrabiblos'' into Latin in the 12th century, "Ptolemaic astrology" became integrated by
Albertus Magnus Albertus Magnus (c. 1200 – 15 November 1280), also known as Saint Albert the Great or Albert of Cologne, was a German Dominican friar, philosopher, scientist, and bishop. Later canonised as a Catholic saint, he was known during his li ...
and
Thomas Aquinas Thomas Aquinas, Dominican Order, OP (; it, Tommaso d'Aquino, lit=Thomas of Aquino, Italy, Aquino; 1225 – 7 March 1274) was an Italian Dominican Order, Dominican friar and Catholic priest, priest who was an influential List of Catholic philo ...
into medieval
Christian Christians () are people who follow or adhere to Christianity, a monotheistic Abrahamic religion based on the life and teachings of Jesus Christ. The words ''Christ'' and ''Christian'' derive from the Koine Greek title ''Christós'' (Χρι� ...
doctrine. Tarnas (1991)
pp.193–194
This
theological Theology is the systematic study of the nature of the divine and, more broadly, of religious belief. It is taught as an academic discipline, typically in universities and seminaries. It occupies itself with the unique content of analyzing the s ...
acceptance encouraged the teaching of Ptolemaic astrology in universities, often linked to medical studies. This, in turn, brought attention in literary works, such as
Dante Dante Alighieri (; – 14 September 1321), probably baptized Durante di Alighiero degli Alighieri and often referred to as Dante (, ), was an Italian poet, writer and philosopher. His ''Divine Comedy'', originally called (modern Italian: ' ...
's, which helped shape the
moral A moral (from Latin ''morālis'') is a message that is conveyed or a lesson to be learned from a story or event. The moral may be left to the hearer, reader, or viewer to determine for themselves, or may be explicitly encapsulated in a maxim. ...
, religious and
cosmological Cosmology () is a branch of physics and metaphysics dealing with the nature of the universe. The term ''cosmology'' was first used in English in 1656 in Thomas Blount's ''Glossographia'', and in 1731 taken up in Latin by German philosopher ...
paradigm In science and philosophy, a paradigm () is a distinct set of concepts or thought patterns, including theories, research methods, postulates, and standards for what constitute legitimate contributions to a field. Etymology ''Paradigm'' comes f ...
of
Western Europe Western Europe is the western region of Europe. The region's countries and territories vary depending on context. The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the ancient Mediterranean ...
during the
Medieval era In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire a ...
. The ''Tetrabiblos'' was largely responsible for laying down the basic precepts of
Renaissance The Renaissance ( , ) , from , with the same meanings. is a period in European history marking the transition from the Middle Ages to modernity and covering the 15th and 16th centuries, characterized by an effort to revive and surpass ide ...
astrology, and was a necessary textbook in some of the finest universities of Renaissance and
early modern Europe Early modern Europe, also referred to as the post-medieval period, is the period of European history between the end of the Middle Ages and the beginning of the Industrial Revolution, roughly the late 15th century to the late 18th century. Histor ...
. Ptolemaic astrology continued to be taught at European universities into the 17th century, but by the mid-17th century the study struggled to maintain its position as one of the respected Liberal sciences. At this time, the contents of the ''Tetrabiblos'' started to draw stigmatisation as part of "a diabolical art of divination". One 17th-century critic was to write of its subject: "no superstitious art is more fitted to forward the aims of the devil than the astrology of Ptolemy". The intellectual standing of astrology collapsed rapidly at the end of the 17th century, but the historical impact of the ''Tetrabiblos'' upon world culture continues to engage the attention of scholars of
classical philosophy This page lists some links to ancient philosophy, namely philosophical thought extending as far as early post-classical history (). Overview Genuine philosophical thought, depending upon original individual insights, arose in many cultures ...
and the history of sciences in antiquity. It also maintains its position as an influential textbook for practitioners of modern western astrology, and English translations of the text were published by
astrologer Astrology is a range of divinatory practices, recognized as pseudoscientific since the 18th century, that claim to discern information about human affairs and terrestrial events by studying the apparent positions of celestial objects. Di ...
s in the 18th, 19th and 20th centuries. The early 20th-century
Humanist Humanism is a philosophical stance that emphasizes the individual and social potential and agency of human beings. It considers human beings the starting point for serious moral and philosophical inquiry. The meaning of the term "human ...
astrologer
Dane Rudhyar Dane Rudhyar (March 23, 1895 – September 13, 1985), born Daniel Chennevière, was a American author, modernist composer and humanistic astrologer. He was a pioneer of modern transpersonal astrology. Biography Dane Rudhyar was born in Paris on ...
reported that the astrology of his era "originated almost entirely in the work of the Alexandrian astrologer, Claudius Ptolemy". Even 21st-century astrological textbooks have described the ''Tetrabiblos'' as being "without a doubt, indispensable for any serious student of astrology". The work's enduring significance is attributed to several factors: Ptolemy's reputation as one of the greatest philosophers and scientists of the ancient world, the text's astrological importance as one of the oldest complete manuals on that subject, Houlding (1993) p.3. and the unprecedented order and quality of Ptolemy's astrological explanations. Riley (1988) p.69. The "outstanding mark of Ptolemy’s astrology" is described as "informed by the philosophical and scientific spirit of his age". Tester (1987)
p.60
Ptolemy wrote at a time when "physics" was defined by
philosophy Philosophy (from , ) is the systematized study of general and fundamental questions, such as those about existence, reason, knowledge, values, mind, and language. Such questions are often posed as problems to be studied or resolved. ...
, and his account of stellar effects was expressed in terms of the four Aristotelian qualities (hot, cold, wet, and dry) set against the philosophical notion of universal unity and cosmic harmony. His objective was to explain the rationale of astrology in such terms, so the work is also notable for its dismissal of astrological practices which lack a direct astronomical basis: The book opens with an explanation of the philosophical framework of astrology which aims to answer the arguments of critics who questioned the subject's validity. Of this,
Lynn Thorndike Lynn Thorndike (24 July 1882, in Lynn, Massachusetts, USA – 28 December 1965, Columbia University Club, New York City) was an American historian of medieval science and alchemy. He was the son of a clergyman, Edward R. Thorndike, and the young ...
, in his ''History of Magic and Experimental Science'', writes: "Only the opponents of astrology appear to have remained ignorant of the ''Tetrabiblos'', continuing to make criticisms of the art which do not apply to Ptolemy's presentation of it or which had been specifically answered by him". Ptolemy was not responsible for originating the astrological techniques he presented in the ''Tetrabiblos''. His contribution was to arrange the material systematically, in order to demonstrate that astrology is based upon logical, hierarchical principles. Astrological influences are frequently referred to the meteorological effects of humoral shifts, which were presumed to result from celestial cycles bringing correlated changes in the heating, cooling, moistening, and drying effects of the atmosphere. The historical importance and influence of the ''Tetrabiblos'' is attested by the many ancient, Medieval and Renaissance commentaries published about it, as well as the many translations and paraphrased editions that aim to reproduce its content in an accessible manner. The Greek text has undergone transmission into Arabic, Latin and many modern languages. The first English translation did not appear until the 18th century, but by the end of the 19th century the American astrologer Luke Broughton reported he had at least half a dozen different English translations in his possession.


Title and date of composition

The commonly known Greek and Latin titles (''Tetrabiblos'' and ''Quadripartitum'' respectively), meaning 'four books', are traditional nicknames Jones (2010) 'Introduction' by Alexander Jones, p.xii: "The ''Tetrabiblos'' (again a nickname - we do not know Ptolemy's own title, but a credible guess is ''Apotelesmatika'', roughly 'Astrological Influences')". for a work which in some Greek manuscripts is entitled , 'Mathematical treatise in four books'. Robbins (1940) 'Translator's Introduction
II, p.x–xi
Frank Eggleston Robbins, editor of the Loeb English translation published in 1940, considered it likely that this was the title used by Ptolemy himself, although he acknowledged that many other Greek manuscripts use the title , 'The prognostics addressed to Syrus'. An ancient anonymous commentary on the work states that some considered the term ''Tetrabiblos'' to be a fictitious name. Hübner, editor of the 1998 Teubner Greek edition, uses the title ''Apotelesmatiká'' (''biblía''), '(books on) effects', which has been followed by recent scholars.Heilen, Stephan, 'Ptolemy's Doctrine of the Terms and its Reception', in Jones (2010)br>p.45
Alexander Jones, editor of the Springer publication ''Ptolemy in Perspective'' (2010), considers that Ptolemy's own title remains unknown, but agrees that the term ''Apotelesmatika'' is "a credible guess". This term is variously translated to mean 'influences', 'effects' or 'prognostics'; reflecting the theme of work, which is concerned with gaining foreknowledge of the effects of predictable astronomical cycles. There is no firmly established date for the compilation of the ''Tetrabiblos'', but Ptolemy discloses in his 'Introductory Address' that he wrote his astrological treatise after completing his astronomical one: the ''
Almagest The ''Almagest'' is a 2nd-century Greek-language mathematical and astronomical treatise on the apparent motions of the stars and planetary paths, written by Claudius Ptolemy ( ). One of the most influential scientific texts in history, it can ...
''. ''Tetrabiblos'' I.1 (Loeb:
p.3
.
Evidence within the ''Almagest'' reveals that the astronomical work could not have been completed before about 145 AD, which demonstrates that Ptolemy wrote the ''Tetrabiblos'' towards the end of his life, sometime between completing the ''Almagest'' and his death, generally reported to be around 168 A.D.


Book I: principles and techniques


Opening chapters

The text begins with Ptolemy's address to "Syrus", an unidentified character to whom all Ptolemy's works are dedicated. In this Ptolemy differentiates between two types of astronomical study: the first (
astronomy Astronomy () is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, g ...
proper) which discovers the astronomical cycles and movements; the second (
astrology Astrology is a range of divinatory practices, recognized as pseudoscientific since the 18th century, that claim to discern information about human affairs and terrestrial events by studying the apparent positions of celestial objects. Di ...
) which investigates the changes these movements bring about. He states that each has its own science and the former is desirable in its own right "even though it does not attain the result given by its combination with the second". This is taken to demonstrate Ptolemy's view that astronomy and astrology are complementary studies, so that whilst astrology is less self-sufficient and factual, its employment makes the practice of astronomy more useful. Lehoux (2006) footnote 28: "Older versions of the history of astronomy tended to make great hay of Ptolemy's separating his astronomy and astrology into two books (the ''Almagest'' and the ''Tetrabiblos''), as though that pointed to doubts Ptolemy had about astrology as a body of knowledge. But Ptolemy is clear that even if it is ''less certain'', astrology is ''more useful'' than astronomy". Although the terms ''astronomia'' and ''astrologia'' were used interchangeably in ancient texts, this also demonstrates the early definition of two differentiated subjects which were discussed at length by Ptolemy in two separate works. Ptolemy states that having dealt with the former subject (astronomy) in its own treatise, he "shall now give an account of the second and less self-sufficient method in a properly philosophical way, so that one whose aim is the truth might never compare its perceptions with the sureness of the first". In this, and further introductory remarks, he reveals his view that astrological prediction is extremely difficult and easily subject to error, but satisfactorily attainable to those who possess the necessary skill and experience, and of too much benefit to be dismissed simply because it can sometimes be mistaken.


Ptolemy's philosophical arguments

Chapters 2 and 3 are important for giving Ptolemy's philosophical defense of his subject. Franz Boll noticed the arguments were paralleled in older sources, particularly those of the
Stoic Stoic may refer to: * An adherent of Stoicism; one whose moral quality is associated with that school of philosophy * STOIC, a programming language * ''Stoic'' (film), a 2009 film by Uwe Boll * ''Stoic'' (mixtape), a 2012 mixtape by rapper T-Pain * ...
philosopher
Posidonius Posidonius (; grc-gre, Ποσειδώνιος , "of Poseidon") "of Apameia" (ὁ Ἀπαμεύς) or "of Rhodes" (ὁ Ῥόδιος) (), was a Greek politician, astronomer, astrologer, geographer, historian, mathematician, and teacher nativ ...
(135 BCE–AD 51 BCE). Equally, Ptolemy's narrative was drawn upon by later
philosophers A philosopher is a person who practices or investigates philosophy. The term ''philosopher'' comes from the grc, φιλόσοφος, , translit=philosophos, meaning 'lover of wisdom'. The coining of the term has been attributed to the Greek th ...
and
astronomers An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, moons, comets and galaxies – in either obse ...
, such as
Johannes Kepler Johannes Kepler (; ; 27 December 1571 – 15 November 1630) was a German astronomer, mathematician, astrologer, natural philosopher and writer on music. He is a key figure in the 17th-century Scientific Revolution, best known for his laws ...
, who used similar examples and the same order of arguments to explain the physical foundation of some astrological claims. Described as "scientifically speaking, perfectly laudable" by one modern commentator, another has condemned these chapters as the place where Ptolemy's "knowledge, intelligence and rhetorical skill" are most "misused". In chapter one Ptolemy asserts the legitimacy of the study and identifies the two main arguments set against it: # the complexity of the subject makes its claim of providing reliable foreknowledge unattainable; # reliable foreknowledge—if it can be attained—would imply such
fatalism Fatalism is a family of related philosophical doctrines that stress the subjugation of all events or actions to fate or destiny, and is commonly associated with the consequent attitude of resignation in the face of future events which are t ...
as to make the subject's purpose useless (since if the future is predictable, anything which is destined to happen will happen whether predicted or not). Ptolemy then answers each criticism in the following two chapters. ;Argument on the extent of astrology's reliability In chapter two Ptolemy maintains that knowledge gained by astronomical means is attainable and he attempts to define its limits according to "Aristotelian-Stoic" logic. Tester (1987)
p.64
He points out how the
Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
has the greatest influence upon the Earth's seasonal and daily cycles, and that most things in nature are synchronised by the
Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...
: He extends this ability to stir the weather and steer the biological patterns of earthly creatures to the
fixed stars In astronomy, fixed stars ( la, stellae fixae) is a term to name the full set of glowing points, astronomical objects actually and mainly stars, that appear not to move relative to one another against the darkness of the night sky in the backgro ...
and
planets A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a youn ...
, so that everything which experiences cycles of growth, or patterns of behaviour, is in some way responsive to the celestial cycles. These bring about elemental changes (hot, windy, snowy or watery conditions, ''etc''): led by the Sun, activated by the Moon and aided by the planetary configurations and the fixed stars'
phenomena A phenomenon ( : phenomena) is an observable event. The term came into its modern philosophical usage through Immanuel Kant, who contrasted it with the noumenon, which ''cannot'' be directly observed. Kant was heavily influenced by Gottfried ...
. The prevailing
meteorological Meteorology is a branch of the atmospheric sciences (which include atmospheric chemistry and physics) with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did not ...
qualities are then considered to determine the
temperament In psychology, temperament broadly refers to consistent individual differences in behavior that are biologically based and are relatively independent of learning, system of values and attitudes. Some researchers point to association of temperam ...
– the quality of the moment of time at a specific place – which is presumed to be impressed, as a sort of temporal imprint, upon the seed of anything which comes into germination or manifestation at that moment in time. Ptolemy admits that successful analysis of this temperament is not easily attained but is capable of being determined by someone who is able to regard the data "both scientifically and by successful conjecture". He questions why, if a person can reliably predict the general weather patterns and their effects upon agricultural seeds and animals from the knowledge of the celestial cycles: Whilst suggesting that such arguments are enough to demonstrate the validity of astrology, Ptolemy accepts that many mistakes are made in its practice – partly because of "evident rascals" who profess to practice it without due knowledge and pretend to foretell things which cannot be naturally known (sometimes using the term 'astrology' for practices which are not true to the genuine study of astrology) and because legitimate practitioners must acquire a magnitude of knowledge and experience within a limited life-span. His summary is that the study is usually only able to give reliable knowledge in general terms; that astrological advice should be welcomed but not expected to be faultless; and that the astrologer should not be criticised but encouraged to integrate non-celestial information within the compilation of a judgement (such as what is known of an individual's ethnic background, nationality and parental influences).


Argument on whether astrology is natural and useful

In chapter three Ptolemy argues that astrological prediction is both natural and beneficial. The translation of these ideas into Latin in the 12th century are described as being "of critical importance" to the adoption of a favourable attitude towards astrology within
Christianity Christianity is an Abrahamic monotheistic religion based on the life and teachings of Jesus of Nazareth. It is the world's largest and most widespread religion with roughly 2.38 billion followers representing one-third of the global popula ...
than it was in the European Dark Ages in the
Medieval period In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire a ...
. Ptolemy first proposes that it is not "useless" to create predictions of what is likely to happen, even if the predictions do not provide the means to avoid impending disaster. This was one of the well known classical criticisms that had been brought to prominence in
Cicero Marcus Tullius Cicero ( ; ; 3 January 106 BC – 7 December 43 BC) was a Roman statesman, lawyer, scholar, philosopher, and academic skeptic, who tried to uphold optimate principles during the political crises that led to the esta ...
's text '' De Divinatione'', in the argument that no good comes from warnings of imminent disasters when they offer no means of escape. Ptolemy gives a more positive view of divination in his assessment of astrology as a subject "by which we gain full view of things human and divine", ''Tetrabiblos'' I.3 (Loeb
pp.21–23
.
which, he argues, gives a better perception of "what is fitting and expedient for the capabilities of each temperament". He views astrology as a subject which encourages enhanced self-knowledge, to be valued as a source of pleasure and well-being; since even if astrology cannot aid in the acquisition of riches or fame; the same can be said of all philosophy, which concerns itself with "greater advantages". Hence, in the case of unfortunate events that will necessarily take place, Ptolemy asserts that astrological prediction still brings benefits, because "foreknowledge accustoms and calms the soul by experience of distant events as though they were present, and prepares it to greet with calm and steadiness whatever comes". Ptolemy's next argument was to avoid the criticisms that arise when the practice of prediction is seen to suggest fatal necessity. This point was crucial to later theological acceptance, since
Medieval In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire a ...
religious doctrine dictates that the individual
soul In many religious and philosophical traditions, there is a belief that a soul is "the immaterial aspect or essence of a human being". Etymology The Modern English noun '' soul'' is derived from Old English ''sāwol, sāwel''. The earliest att ...
must possess
free will Free will is the capacity of agents to choose between different possible courses of action unimpeded. Free will is closely linked to the concepts of moral responsibility, praise, culpability, sin, and other judgements which apply only to ac ...
, in order to be responsible for its own choices and the consequences that flow from them. Gerard of Feltre's 13th-century text ''Summa on the Stars'' demonstrates the problem that astrological determinism creates for the theological argument: "If the stars make a man a murderer or a thief, then all the more it is the first cause, God, who does this, which it is shameful to suggest". Ptolemy's comments counter the criticism by proposing that whilst the celestial cycles are entirely reliable and "eternally performed in accordance with divine, unchangeable destiny", all earthly things are also subject to "a natural and mutable fate, and in drawing its first causes from above it is governed by chance and natural sequence". He therefore declares that nothing is irrevocably ordained, and we are not to imagine that "events attend mankind as the result of the heavenly cause as if … destined to take place by necessity without the possibility of any other cause whatever interfering". In this discussion Ptolemy makes a point that was to be called upon by many later astrological writers, that "the lesser cause always yields to the stronger". ''Tetrabiblos'' I.3 (Loeb
pp.25–29
.
He sees an individual as unable to resist the greater cycles of change which happen to the wider community, so even a man whose horoscope indicates gain may perish at a time that his community is struck by natural disaster or pestilence. However, Ptolemy also maintains that disastrous events will only follow a natural course if no counter action is taken to avert the problem, as when "future happenings to men are not known, or if they are known and the remedies are not applied". He takes a balanced position in the argument of fate versus free will in writing that certain things, because their effective causes are numerous, become inevitable, whilst others are able to be averted by the act of astrological prediction. The astrologer's position is compared to that of the physician, who must be able to recognise beforehand which ailments are always fatal, and which admit of aid. It is therefore reasonable, in Ptolemy's estimation, to moderate actions with awareness of how the prevailing and future temperament prospers or injures the natal temperament, or to elect to act at a time that is astrologically suitable to the activity – just as it is deemed rational to use knowledge of the stars to ensure safety at sea; to use knowledge of the lunar cycle to ensure successful breeding and sowing, or to cool ourselves against the extremes of temperature in order that we suffer less. Ptolemy's philosophical conclusion on the subject, which helped to secure its intellectual standing until the 18th century, is thus: "even if it be not entirely infallible, at least its possibilities have appeared worthy of the highest regard". Having justified his intellectual involvement in the study, according to the philosophical principles of his day, Ptolemy then turns his attention to the practical theory of astrology, and the rationale that lies behind the arrangement of its principles.


Introduction of principles

One of the unique features of the ''Tetrabiblos'', amongst the astrological texts of its period, is the extent to which the first book not only introduces the basic astrological principles, but synthesises and explains the reasoning behind their reported associations in line with
Aristotelian philosophy Aristotelianism ( ) is a philosophical tradition inspired by the work of Aristotle, usually characterized by deductive logic and an analytic inductive method in the study of natural philosophy and metaphysics. It covers the treatment of the soci ...
. Riley (1974) p.255. Chapter four, for example, explains the "power of the planets" through their associations with the creative humoral qualities of warmth or moisture, or the reductive qualities of cold and dryness. Tester (1987)
p.59
Hence Mars is described as a destructive planet because its humoral association is excessive dryness, whilst Jupiter is defined as temperate and fertilising because its association is moderate warmth and humidity. These associations are based on the arrangements of the planets with regard to the Sun, as perceived from the geocentric perspective, by which their orbits are measured is if they are centred upon the Earth. Uniting these Aristotelian principles with a prevalent Greek philosophy employed by
Zeno of Citium Zeno of Citium (; grc-x-koine, Ζήνων ὁ Κιτιεύς, ; c. 334 – c. 262 BC) was a Hellenistic philosopher from Citium (, ), Cyprus. Zeno was the founder of the Stoic school of philosophy, which he taught in Athens from about 300 B ...
and the
Pythagorean Pythagorean, meaning of or pertaining to the ancient Ionian mathematician, philosopher, and music theorist Pythagoras, may refer to: Philosophy * Pythagoreanism, the esoteric and metaphysical beliefs purported to have been held by Pythagoras * Ne ...
s, the next three chapters arrange the planets into pairs of opposites. They may be benefic (moderately warming or moistening) or malefic (excessively cooling or drying); masculine (drying) or feminine (moistening); active and diurnal (suited to the qualities of the day and aligned with the nature of the Sun) or passive and
nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...
(suited to the qualities of the night and aligned with the nature of the Moon). Since these humoral associations derive from configurations with the Sun, chapter eight describes how they are subtly modified according to the phase of each planet's
synodic cycle Synodic, may refer to: * Synodic day * Synodic month * Synodic orbital period, synodic year or synodic time, the time of an celestial object An astronomical object, celestial object, stellar object or heavenly body is a naturally occurring ...
with the Sun. Chapter nine discusses the "power of the fixed stars". Here, rather than give direct humoral associations, Ptolemy describes their "temperatures" as being like that of the planets he has already defined. Hence
Aldebaran Aldebaran (Arabic: “The Follower”, "الدبران") is the brightest star in the zodiac constellation of Taurus. It has the Bayer designation α Tauri, which is Latinized to Alpha Tauri and abbreviated Alpha Tau or α Tau. Aldeba ...
("called the Torch") is described as having "a temperature like that of Mars", whilst other stars in the Hyades are "like that of Saturn and moderately like that of Mercury". At the end of the chapter Ptolemy clarifies that these are not his proposals, but are drawn from historical sources, being "the observations of the effects of the stars themselves as made by our predecessors". Chapter ten returns to the humoral theme more explicitly, clarifying that the
zodiac The zodiac is a belt-shaped region of the sky that extends approximately 8° north or south (as measured in celestial latitude) of the ecliptic, the apparent path of the Sun across the celestial sphere over the course of the year. The pa ...
is aligned to the
season A season is a division of the year based on changes in weather, ecology, and the number of daylight hours in a given region. On Earth, seasons are the result of the axial parallelism of Earth's tilted orbit around the Sun. In temperate and ...
s and so expressive of the shifting emphasis through moisture, warmth, dryness and cold, (as brought about by
spring Spring(s) may refer to: Common uses * Spring (season), a season of the year * Spring (device), a mechanical device that stores energy * Spring (hydrology), a natural source of water * Spring (mathematics), a geometric surface in the shape of a h ...
,
summer Summer is the hottest of the four temperate seasons, occurring after spring and before autumn. At or centred on the summer solstice, the earliest sunrise and latest sunset occurs, daylight hours are longest and dark hours are shortest, wit ...
,
autumn Autumn, also known as fall in American English and Canadian English, is one of the four temperate seasons on Earth. Outside the tropics, autumn marks the transition from summer to winter, in September ( Northern Hemisphere) or March ( ...
, and
winter Winter is the coldest season of the year in polar and temperate climates. It occurs after autumn and before spring. The tilt of Earth's axis causes seasons; winter occurs when a hemisphere is oriented away from the Sun. Different cultur ...
). Similarly, the four angles of the chart present an humoral emphasis through association with the effects of the four cardinal
winds Wind is the natural movement of air or other gases relative to a planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few ...
that blow from their aligned directions. The remainder of book one (up to the final two chapters which concern the
planetary phase A planetary phase is a certain portion of a planet's area that reflects sunlight as viewed from a given vantage point, as well as the period of time during which it occurs. Inferior planets The two inferior planets, Mercury and Venus, which h ...
s and aspectual applications), presents the rulerships, divisions, and configurations of the
zodiac signs In Western astrology, astrological signs are the twelve 30-degree sectors that make up Earth's 360-degree orbit around the Sun. The signs enumerate from the first day of spring, known as the First Point of Aries, which is the vernal equinox. ...
, most of which are related to astronomical definitions, seasonal effects, physics and
geometry Geometry (; ) is, with arithmetic, one of the oldest branches of mathematics. It is concerned with properties of space such as the distance, shape, size, and relative position of figures. A mathematician who works in the field of geometry is c ...
. Geometrical principles are used to define the favourable or unfavourable quality of
astrological aspect In astrology, an aspect is an angle that planets make to each other in the Horoscope; as well as to the Ascendant, Midheaven, Descendant, Lower Midheaven, and other points of astrological interest. As viewed from Earth, aspects are measured ...
s, based on the angular relationship of planets and signs with
ecliptic The ecliptic or ecliptic plane is the orbital plane of the Earth around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic agains ...
degrees. In Ptolemy's era the boundaries of the zodiac signs were close to those of the visible
constellation A constellation is an area on the celestial sphere in which a group of visible stars forms a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the earliest constellation ...
s whose names they bear, but Ptolemy demonstrates the theoretical distinction between the two frames of reference in describing the starting point of the zodiac as fixed, not to the stars, but to the mathematically calculated vernal equinox. This determines the seasonally based
tropical zodiac The zodiac is a belt-shaped region of the sky that extends approximately 8° north or south (as measured in celestial latitude) of the ecliptic, the apparent path of the Sun across the celestial sphere over the course of the year. The path ...
which takes its name from the Greek word τροπικός ''tropikos'': ‘of the turning’, because it is set by the turn of the seasons and, being subject to
precession Precession is a change in the orientation of the rotational axis of a rotating body. In an appropriate reference frame it can be defined as a change in the first Euler angle, whereas the third Euler angle defines the rotation itself. In oth ...
, experiences a slow and gradual revolution through the visible constellations. For the same reason, the signs that mark the Sun's summer and winter
solstice A solstice is an event that occurs when the Sun appears to reach its most northerly or southerly excursion relative to the celestial equator on the celestial sphere. Two solstices occur annually, around June 21 and December 21. In many count ...
points (
Cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...
and Capricorn) are described as the 'tropical signs', since these are the places where the Sun 'turns' its direction in
celestial latitude Astronomical coordinate systems are organized arrangements for specifying positions of satellites, planets, stars, galaxies, and other celestial objects relative to physical reference points available to a situated observer (e.g. the true horizon ...
, (thereby defining the terrestrial
circles of latitude A circle of latitude or line of latitude on Earth is an abstract east– west small circle connecting all locations around Earth (ignoring elevation) at a given latitude coordinate line. Circles of latitude are often called parallels bec ...
known as the
Tropic of Cancer The Tropic of Cancer, which is also referred to as the Northern Tropic, is the most northerly circle of latitude on Earth at which the Sun can be directly overhead. This occurs on the June solstice, when the Northern Hemisphere is tilted towa ...
and the
Tropic of Capricorn The Tropic of Capricorn (or the Southern Tropic) is the circle of latitude that contains the subsolar point at the December (or southern) solstice. It is thus the southernmost latitude where the Sun can be seen directly overhead. It also reac ...
). Whereas other ancient astrological writers gave their emphasis to the astrological interpretation of such definitions (for example, in describing how tropical signs are indicative of quickly changing situations), Ptolemy's focus is notably different; given to the astronomical and philosophical factors that underlie the definitions rather than their astrological meaning in practice. Ptolemy explains that the definitions of the zodiac are not his own, but present "the natural characters of the zodiacal signs, as they have been handed down by tradition". His approach finds elegant expression where he is demonstrating the logic of schematic arrangements (such as the philosophical principles behind the planetary rulership of signs), but is noted to convey detachment in regard to the elements of astrology that are not so obviously plausible. This can be seen in the way that Ptolemy avoids going into detail on the facets of astrology that rely on
mythological Myth is a folklore genre consisting of narratives that play a fundamental role in a society, such as foundational tales or origin myths. Since "myth" is widely used to imply that a story is not objectively true, the identification of a narrat ...
, or
symbol A symbol is a mark, sign, or word that indicates, signifies, or is understood as representing an idea, object, or relationship. Symbols allow people to go beyond what is known or seen by creating linkages between otherwise very different conc ...
ic associations, and how he is willing to outline the reasoning behind conflicting astrological proposals without revealing any personal preference for one scheme over another. Some commentators have viewed Ptolemy's comparatively dispassionate approach towards points of astrological contention as reason to suppose he was more interested in the theoretical principles than the actual practice of astrology. On the other hand, the objective tone that marks his style; his assertion that the subject is natural (by which he makes no demand for oaths of secrecy from its students as some contemporaries do); and the way he shows respectful reference to alternative views without vilifying authors whose practices might differ from his own, all helped to secure the text's historical reputation as an intellectually superior one.
Classics Classics or classical studies is the study of classical antiquity. In the Western world, classics traditionally refers to the study of Classical Greek and Roman literature and their related original languages, Ancient Greek and Latin. Classics ...
scholar Mark Riley raised these points in his assessment that Ptolemy approached the subject of astrology with exactly the same theoretical inclination that he applied to astronomy,
geography Geography (from Greek: , ''geographia''. Combination of Greek words ‘Geo’ (The Earth) and ‘Graphien’ (to describe), literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, an ...
and the other sciences on which he wrote. This distinctive style of approach led Riley to conclude: "The respect shown to Ptolemy’s work by all later astrologers was due, not to its usefulness to the practitioner, but to his magisterial synthesis of astrology and science".


Book II: Mundane astrology

Book II presents Ptolemy's treatise on
mundane astrology Mundane astrology, also known as political astrology, is the branch of astrology dealing with politics, the government, and the laws governing a particular nation, state, or city. The name derives name from the Latin term ''mundus'', 'world'. ...
. This offers a comprehensive review of
ethnic stereotypes An ethnic stereotype, racial stereotype or cultural stereotype involves part of a system of beliefs about typical characteristics of members of a given ethnic group, their status, societal and cultural norms. A national stereotype, or nation ...
,
eclipses An eclipse is an astronomical event that occurs when an astronomical object or spacecraft is temporarily obscured, by passing into the shadow of another body or by having another body pass between it and the viewer. This alignment of three ce ...
, significations of
comets A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...
and seasonal lunations, as used in the prediction of national economics, wars, epidemics, natural disasters and weather patterns. No other surviving ancient text offers a comparable account of this topic, in terms of the breadth and depth of detail offered by Ptolemy. Although no demonstrated examples are given, he writes with authority in this branch of his subject, which suggests it was of particular interest to him. Modern commentators have remarked that Ptolemy was "consciously taking a different approach" to contrast "with the 'old', infinitely complicated methods". Ptolemy begins by stating he has briefly reviewed the important principles and will now develop the details of astrology in the appropriate order. His point is that astrological assessment of any 'particular' individual must rest upon prior knowledge of the 'general' temperament of their ethnic type; and that the circumstances of individual lives are subsumed, to some extent, within the fate of their community. The second chapter gives a broad generalisation of how differences in physical traits occur between the inhabitants of the various
climes The climes (singular ''clime''; also ''clima'', plural ''climata'', from Greek κλίμα ''klima'', plural κλίματα ''klimata'', meaning "inclination" or "slope") in classical Greco-Roman geography and astronomy were the divisions of ...
(a demarcation based on latitude). Communities that live close to the equator, for example, are described as having black skins, small statures, and thick woolly hair, as a protective response to the burning heat of that location. By contrast, communities that have settled in high northern regions are defined by their colder environment and its greater share of moisture. Their bodily forms are paler, taller, with finer hair, and in their characteristics they are described as "somewhat cold in nature". ''Tetrabiblos'' II.2 (Loeb
p.123, 127
.
Both types are described as lacking civilisation because of the extremes of their environment, whereas communities that live in temperate regions are medium in colouring, moderate in stature and enjoy a more equable lifestyle. The several regions are similarly defined according to the mix that arises within this kind of analysis. Ptolemy explains that such considerations are only dealt with summarily, as a background consideration for what follows. He also makes clear that such traits are to be found "generally present, but not in every individual". In chapter 3 Ptolemy unites his interests in astrology and geography, to outline the astrological associations of "our inhabited world". Maps based on Ptolemy's ''
Geographica The ''Geographica'' (Ancient Greek: Γεωγραφικά ''Geōgraphiká''), or ''Geography'', is an encyclopedia of geographical knowledge, consisting of 17 'books', written in Greek and attributed to Strabo, an educated citizen of the Roman ...
'' show Ptolemy's definition of the inhabited world as (roughly) extending from the equator to latitude 66°N, covering the land mass between the Atlantic Ocean and East China Sea. Ptolemy extends the logic given in ancient Babylonian texts where the four quarters of the known world are attributed to the four
triplicity In astrology, a triplicity is a group of three signs belonging to the same element. Trines Western astrology assumes that each sign of the same triplicity is 120 degrees apart, forming angles to one another called trines, which are each equival ...
arrangements of the zodiac. The attribution is based on association between the planets that govern the triplicities and the directions and winds those planets are affiliated with. For example, the 'Aries triplicity' (which includes Aries, Leo and Sagittarius) is chiefly dominated by Jupiter and assisted by Mars. Jupiter rules the north wind and Mars the west wind; therefore this triplicity governs the north-west quarter of Ptolemy's "inhabited world": the area known as Europe. Again, these divisions are general, and specific rulership of each nation is modified by location and observed cultural distinctions. For example, in Europe, only those regions that lie to the north-west extremes are fully attributed to Jupiter and Mars, since those that lie towards the centre of the inhabited area incline towards the influence of opposing regions. ''Tetrabiblos'' II.3 (Loeb
pp.131–137
.
In this way, the "inhabited region" experiences a drift of astrological correspondence rather than sharp divisions within its quarters, and independent nations are variously affiliated with the signs of each triplicity and the planets that rule them. Ptolemy names Britain and Spain as two nations appropriately placed in the north-west quarter to accept the rulership of Jupiter and Mars. Such nations are described as "independent, liberty-loving, fond of arms, industrious", based on characteristics attributed to those planets. Being predominantly governed by masculine planets they are also "without passion for women and look down upon the pleasures of love". Observed characteristics influence his categorisation of Britain as having a closer affinity with Aries and Mars (by which "for the most part its inhabitants are fiercer, more headstrong and bestial"), whilst Spain is reported to be more subject to Sagittarius and Jupiter, (from which is evidenced "their independence, simplicity and love of cleanliness"). Though Ptolemy describes his analysis as a "brief exposition", ''Tetrabiblos'' II.3 (Loeb
pp.157–161
.
the chapter builds into an extensive association between planets, zodiac signs and the national characteristics of 73 nations. It concludes with three additional assertions which act as core principles of mundane astrology: # Each of the fixed stars has familiarity with the countries attributed to the sign of its ecliptic rising. # The time of the first founding of a city (or nation) can be used in a similar way to an individual
horoscope A horoscope (or other commonly used names for the horoscope in English include natal chart, astrological chart, astro-chart, celestial map, sky-map, star-chart, cosmogram, vitasphere, radical chart, radix, chart wheel or simply chart) is an as ...
, to astrologically establish the characteristics and experiences of that city. The most significant considerations are the regions of the zodiac which mark the place of the Sun and Moon, and the four angles of the chart – in particular the
ascendant The ascendant (Asc, Asc or As) is the astrological sign on the eastern horizon when the person was born. According to certain astrological theories, celestial phenomena reflect or influence human activity on the principle of " as above, so bel ...
. # If the time of the foundation of the city or nation is not known, a similar use can be made of the horoscope of whoever holds office or is king at the time, with particular attention given to the
midheaven A horoscope (or other commonly used names for the horoscope in English include natal chart, astrological chart, astro-chart, celestial map, sky-map, star-chart, cosmogram, vitasphere, radical chart, radix, chart wheel or simply chart) is an ast ...
of that chart.


Use of eclipses

The remainder of the book shows how this information is used in the prediction of mundane events. Focus is given to eclipses, as the "first and most potent" cause of change, supplemented by examination of the 'stations' of the
superior planets In the Solar System, a planet is said to be inferior or interior with respect to another planet if its orbit lies inside the other planet's orbit around the Sun. In this situation, the latter planet is said to be superior to the former. In the ...
: Saturn, Jupiter and Mars. Although eclipses are deemed relevant to any nation affiliated with the zodiac signs in which they occur, Ptolemy's scrutiny is reserved for regions where they are visible, which he argues will manifest the effects most noticeably. The period of obscuration determines the endurance of the effect, with each hour proportioning to years for a solar eclipse and months for a lunar eclipse. The location of the eclipse with relation to the horizon is then used to judge whether the effects are most prevalent at the beginning, middle or end of the period, with times of intensification identified by planetary contacts to the degree of the eclipse which occur within this period. Chapter 7 begins the examination of what type of event will manifest. This is judged by the angle of the horizon which precedes the eclipse in the chart set for the location under scrutiny and the planet(s) that dominate this angle by rulership and powerful aspectual connections. Whether the predicted effect is beneficial or destructive depends on the condition of these planets, whilst the type of manifestation is judged by the zodiac signs, fixed stars and constellations involved. The resulting prediction is of relevance to nations, but Ptolemy points out that certain individuals are more resonant to the effects than others; namely those have the Sun or Moon in their horoscopes in the same degree as the eclipse, or the degree that directly opposes it. Within his ''Almagest'' Ptolemy explains that he had access to eclipse records kept for 900 years since the beginning of the reign of king
Nabonassar Nabû-nāṣir was the king of Babylon from 747 to 734 BC. He deposed a foreign Chaldean usurper named Nabu-shuma-ishkun, bringing native rule back to Babylon after twenty-three years of Chaldean rule. His reign saw the beginning of a new er ...
(747 BC). In chapter 9 of the ''Tetrabiblos'' he shows knowledge of the Babylonian lore that accompanied these records in detailing the omens based on visual phenomena. The colours of eclipses and "the formations that occur near them, such as rods, halos, and the like" are considered along with the astrological significance of comets, in whether they take the form of "'beams', 'trumpets', 'jars', and the like". Meaning is derived from their position relative to the Sun and assessment of "the parts of the zodiac in which their heads appear and through the directions in which the shapes of their tails point". It is noted that here Ptolemy uses principles that fall outside the neat theoretical logic he presents in book I, being explicable only in terms of the mythological and omen tradition inherited from his ancient sources. He also defends the subjective nature of the analysis involved, asserting that it would be impossible to mention the proper outcome of all this investigation, which calls for enterprise and ingenuity from the astrologer creating the judgement. The remaining chapters of book II are dedicated to meteorological matters. Chapter 10 specifies that the new or full Moon preceding the Sun's ingress into Aries can be used as a starting point for investigations concerning the weather patterns of the year. Lunations which precede the Sun's ingress into any the other equinoctial and solstice signs (Cancer, Libra and Capricorn) can also be used for seasonal concerns, and within these "monthly investigations" bring more particular details based on lunations and the conjunctions of the planets. The recorded weather effects of the fixed stars in the zodiac constellations are systematically discussed, concluding with the relevance of generally observed sky phenomena such as shooting stars, cloud formations and rainbows. These final considerations are expected to add localised details to the original exploration of eclipse cycles. Ptolemy's theme throughout the book is that charts of this nature cannot be judged in isolation, but are to be understood within the pattern of cycles to which they belong, and where there are strong connections between the degree points involved; for: With the astrologer expected to have knowledge and awareness of the mundane cycles that outline the background principles of the personal horoscope, Ptolemy closes this book with the promise that the next will supply "with due order" the procedure which allows predictions based on the horoscopes of individuals.


Book III: Individual horoscopes (genetic influences and predispositions)

Books III and IV explore what Ptolemy terms "the genethlialogical art": the interpretation of a horoscope set for the moment of the birth of an individual. ''Tetrabiblos'' III.1 (Loeb
pp.221–7
.
He explains that there are several cycles of life to consider but the starting point for all investigation is the time of conception or birth. The former "the genesis of the seed"” allows knowledge of events that precede the birth; the latter "the genesis of the man" is "more perfect in potentiality" because when the child leaves the womb and comes "forth into the light under the appropriate conformation of the heavens" the temperament, disposition and physical form of the body is set. The two moments are described as being linked by a "very similar causative power", so that the seed of the conception takes independent form at an astrologically suitable moment, whereby the impulse to give birth occurs under a "configuration of similar type to that which governed the child's formation in detail in the first place". Chapter 2 continues this theme in discussing the importance of calculating the precise degree of the ascendant at birth, the difficulty of recording local time precisely enough to establish this, and the methods available for
rectification Rectification has the following technical meanings: Mathematics * Rectification (geometry), truncating a polytope by marking the midpoints of all its edges, and cutting off its vertices at those points * Rectifiable curve, in mathematics * Recti ...
(''i.e''., ensuring the chart is correct). Chapter 3 describes how the analysis of the chart is divided into predictions of: # essential, genetic qualities established prior to birth (such family and parental influences), # those that become known at the birth (such as the sex of the child and birth defects), and # those that can only be known post-natally (such as length of life, the quality of the mind, illnesses, marriage, children, and material fortunes). Ptolemy explains the order by which each theme becomes relevant, and follows this in his arrangement of topics presented in the remaining chapters of books III and IV. First he deals with the prenatal matters, covering the astrological significators of the parents in chapter 4, and siblings in chapter 5. Then he deals with the matters "directly concerned with the birth", explaining how to judge such issues as whether the child will be male or female (ch.6); whether the birth will produce twins or multiple children (ch.7); and whether it will involve physical defects or monstrous forms; if so, whether these are accompanied by mental deficiency, notability or honour (ch.8). The exploration of post-natal concerns begins in chapter 9 with a review of astrological factors that occur when children are not reared. This considers the indications of still births and babies that seem "half-dead", or those that have been left exposed (including whether there is possibility they may be taken up and live). Chapter 10 then details the techniques for establishing the length of life under normal circumstances. This is an important and lengthy passage of text, the techniques of which require precise astronomical detail and advanced knowledge of complex progressive techniques. Jim Tester has commented on how Ptolemy goes into an unusual level of detail in a responsibility that Bouché-Leclercq described as "the chief task of astrology, the operation judged most difficult by practitioners, most dangerous and damnable by its enemies". Such a prediction involves judicial skill as well as mathematical expertise since several 'destructive' periods may be identified but countered by other, protective astrological influences, resulting in periods of danger or illness that does not lead to death. This is followed, in chapter 11, by the astrological principles from which judgement is made of bodily appearance and temperament. The planetary significations follow the logic of their humoral associations, so that Jupiter (associated with warmth and moisture, an humoral combination which promotes growth) gives largeness in bodily form. Since these define, to some extent, predisposition towards bodily afflictions, there is a natural flow towards the content of chapter 12, which focuses on the astrological significators relating to injuries and diseases. The details of planetary associations with bodily organs and functions are given, such as Saturn ruling the spleen and Jupiter the lungs. Jim Tester has pointed out that several lists of this type exist "more or less agreeing in detail". Tester (1987)
p.61
The third book concludes with a discussion in chapters 13 and 14 of what is described as a "largely overlooked" facet of Ptolemaic doctrine: the "psychological" one, which concerns the quality of the soul (or ''psyche'').Campion, Nicholas, 'Astronomy and the Soul', in Tymieniecka (2010) p.250. Historian
Nicholas Campion Nicholas Campion (born 4 March 1953) is a British astrologer and historian of astrology and cultural astronomy. He is the author of a number of books and currently pursues an academic career. Career Astrology Campion is a former ''Daily M ...
has discussed the roots of the notion that celestial and psychological realms are connected, which can be traced to the 6th century BC, and in Ptolemy's case presents a mixture of Aristotelian and
Stoic Stoic may refer to: * An adherent of Stoicism; one whose moral quality is associated with that school of philosophy * STOIC, a programming language * ''Stoic'' (film), a 2009 film by Uwe Boll * ''Stoic'' (mixtape), a 2012 mixtape by rapper T-Pain * ...
philosophy, resting on the
Platonic Plato's influence on Western culture was so profound that several different concepts are linked by being called Platonic or Platonist, for accepting some assumptions of Platonism, but which do not imply acceptance of that philosophy as a whole. It ...
view that "the soul comes from the heavens" which explains "how human character comes to be determined by the heavens". The soul, for Ptolemy, includes the faculty for conscious reasoning, which is rational and attributed to the condition of Mercury, and the subconscious and unconscious elements of the mind (the "sensory and irrational part"), which is sensitive and attributed to the condition of the Moon. These two chapters make analysis of instinctual impulses and moral inclinations, being concerned with psychological motives and behavioural expression rather than the physical temperament described in chapter 11. Diseases of the soul are defined as "affections which are utterly disproportionate and as it were pathological" ''Tetrabiblos'' III.14 (Loeb
pp.365–9
.
including insanity, inability to exercise moderation or restraint, instability of the emotions, depraved sexuality, morbid perversions, and violent afflictions of the intellectual and passive parts of the mind. The astrological explanations are mainly related to the exaggerated influence of destructive planets which are also in difficult configurations with Mercury and the Sun or Moon, or the planet associated with the psychological impulse (for example, Venus in matters of sexuality). Campion has pointed out that these planetary associations with psychological qualities are not original to Ptolemy, being present in the ''
Corpus Hermeticum The is a collection of 17 Greek writings whose authorship is traditionally attributed to the legendary Hellenistic figure Hermes Trismegistus, a syncretic combination of the Greek god Hermes and the Egyptian god Thoth. The treatises were or ...
'' which was in circulation in Alexandria at the time Ptolemy compiled his text. Within this book Ptolemy has surveyed all the topics that relate to inner qualities, genetic patterns, predispositions and the natural tendencies present from birth. His exploration of individual horoscopes continues into book IV, the only distinction of content being that subsequent topics relate to material matters and life experiences: what Ptolemy refers to as "external accidentals". ''Tetrabiblos'' IV.1 (Loeb
p.373
.


Book IV: Individual horoscopes (external accidentals)

Book IV is presented with a brief introduction to reaffirm the arrangement of content as previously described. It starts with the topics of riches and honour. Ptolemy says: "as material fortune is associated with the properties of the body, so honour belongs to those of the soul". Chapter 2, on material wealth, employs the "so-called ' Lot of Fortune'" although Ptolemy's instruction conflicts with that of many of his contemporaries in stating that for its calculation "we measure from the horoscope the distance from the sun to the moon, in both diurnal and nocturnal nativities". Ptolemy's reputation ensured this approach to calculation was adopted by many later Medieval and Renaissance astrologers, although it is now realised that most Hellenistic astrologers reversed the formula of calculation for nocturnal births. It is notable that in his discussion "Of the fortune of Dignity", in chapter three, Ptolemy makes no reference to the Lot of Spirit (or ''Daimon''), which would normally be used as the spiritual counterpart to the material wealth and happiness associated with the Lot of Fortune. This is viewed as a demonstration of his general dislike (declared in bk. III.3) for "lots and numbers of which no reasonable explanation can be given". The subsequent chapter, the title of which is translated by Robbins as 'Of the Quality of Action', concerns professional inclinations and the significators of career advance (or decline). This is followed by the treatment of marriage in chapter 5, which is primarily referred to the Moon in a man's chart, to describe his wife, and the Sun in a woman's chart to describe her husband. Here Ptolemy shows employment of the astrological technique known as synastry, in which the planetary positions of two separate horoscopes are compared with each other for indications of relationship harmony or enmity. The next four chapters complete the survey of natal themes, dealing with the topics of children (ch.6); friends and enemies (ch.7); the dangers of foreign travel (ch.8) and the quality (or type) of death (ch.9 – as opposed to the time of death considered in III.10). The final chapter of the work is described as "a curious one" for introducing a separate theme at the end of the book. This refers to the seven 'ages of man', which Ptolemy briefly mentioned in III.1 as a matter which varies the emphasis of astrological configurations according to the time in life they occur: "we predict events that will come about at specific times and vary in degree, following the so called ages of life. His argument is that, just as an astrologer must consider cultural differences "lest he mistake the appropriate customs and manners by assigning, for example, marriage with a sister to one who is Italian by race, instead of to the Egyptian as he should", ''Tetrabiblos'' IV.10 (Loeb:
pp.439–441
.
it is necessary to consider the age in life that important astrological events occur. This is to ensure the prediction will "harmonise those details which are contemplated in temporal terms with that which is suitable and possible for persons in the various age-classes" and avoid out-of-context predictions such as imminent marriage for a young child, or "to an extremely old man the begetting of children or anything else that fits younger men". This leads into a discussion of the planetary themes of the seven ages of life which: The information in the passage can be summarised as follows: The book ends with a brief discussion of astronomical and symbolic cycles used in the prediction of timed events, which includes mention of (primary) directions, annual profections, ingresses, lunations and transits. The translator of the Loeb 1940 English translation, F. E. Robbins, reports a "puzzling problem" regarding the final paragraph of the book. One group of manuscripts have either been left unconcluded or supplied with text that matches an ''Anonymous Paraphrase'' of the work (speculatively attributed to Proclus); the other presents text which is the same in general content, but longer, according with manuscripts that were transmitted through Arabic translations. Robbins (1940) 'Translator's Introduction',
p.xxi
Robbins considers it certain that the ending which concurs with the text of the ''Paraphrase'' is spurious. Robert Schmidt, the English translator of the later Project Hindsight edition agrees with his choice, stating that the text of the latter "sounds more generally Ptolemaic". Robbins explains that the lack of an ending usually occurs when ancient books are compiled in the form of a
codex The codex (plural codices ) was the historical ancestor of the modern book. Instead of being composed of sheets of paper, it used sheets of vellum, papyrus, or other materials. The term ''codex'' is often used for ancient manuscript books, with ...
rather than a roll. Since the ''Paraphrase'' edition of the ''Tetrabiblos'' aimed to present the work's meaning without Ptolemy's own complicated style of text construction, Robbins says that he "cannot conceive how anyone (except perhaps Ptolemy) could have reversed the process and evolved the tortuous, crabbed Greek of the latter from the comparatively simple language of the former". He therefore offers both versions of the ending whilst lending his support to that which is found in the Arabic version of the text. This has the book conclude with Ptolemy declaring "since the topic of nativities has been summarily reviewed, it would be well to bring this procedure also to a fitting close".


Criticism

Despite Ptolomy's prominence as a philosopher, the Dutch historian of science Eduard Jan Dijksterhuis criticizes the ''Tetrabiblos'', stating that "it only remain puzzling that the very writer of the ''Almagest'', who had taught how to develop astronomy from accurate observations and mathematical constructions, could put together such a system of superficial analogies and unfounded assertions."


Editions and translations

No original manuscripts of the text have survived; its contents are known from translations, fragments, paraphrased copies, commentaries and later Greek manuscripts. Astrological researcher Deborah Houlding, in an analysis of how specific points agree or vary between different editions, suggests that areas of conflicting details have been affected by three main streams of transmission: manuscripts that have passed through Arabic translation; those based on a paraphrased edition, and manuscripts that are dated four centuries later than the Arabic ones, but which have not undergone translation out of Greek.Houlding, Deborah 'Ptolemy's terms and conditions: the transmission of Ptolemy's terms; an historical overview, comparison and interpretation', in Burnett and Greenbaum (2007); reproduced online a
Skyscript
(see p.3–4,6,11,15); retrieved 7 December 2011.


Arabic translations

The oldest extant manuscript is an Arabic translation compiled in the 9th century by
Hunayn ibn Ishaq Hunayn ibn Ishaq al-Ibadi (also Hunain or Hunein) ( ar, أبو زيد حنين بن إسحاق العبادي; (809–873) was an influential Nestorian Christian translator, scholar, physician, and scientist. During the apex of the Islamic ...
. This was first translated into Latin, in Barcelona, by Plato de Tivoli in 1138 and became influential as the first complete introduction of Ptolemy's astrological work in Medieval Europe. It survives in at least nine manuscripts and five Renaissance printings. Other Latin translations made from Arabic sources include an anonymous (unpublished) work compiled in 1206 and another of the 13th century by Egidio Tebaldi (Aegidius de Thebaldis). Typically, the Latin translations made from Arabic texts were circulated with a commentary compiled by Ali ibn Ridwan (Haly) in the 11th century. Westman (2011) p.43 Egidio Tebaldi's translation was first published by
Erhard Ratdolt Erhard Ratdolt (1442–1528) was an early German printer from Augsburg. He was active as a printer in Venice from 1476 to 1486, and afterwards in Augsburg. From 1475 to 1478 he was in partnership with two other German printers. The first book ...
in 1484 together with Haly's commentary and a "pseudo-Ptolemaic" list of aphorisms known as the ''
Centiloquium The ''Centiloquium'' (= "one hundred sayings"), also called ''Ptolemy's Centiloquium'', is a collection of one hundred aphorisms about astrology and astrological rules. It is first recorded at the start of the tenth century CE, when a commentary ...
''. This has been described as "the creature of late-fifteenth-century Italian presses".


Paraphrase based editions

An anonymous Greek paraphrase is speculatively attributed to the 5th-century philosopher
Proclus Proclus Lycius (; 8 February 412 – 17 April 485), called Proclus the Successor ( grc-gre, Πρόκλος ὁ Διάδοχος, ''Próklos ho Diádokhos''), was a Greek Neoplatonist philosopher, one of the last major classical philosophe ...
. It is often referred to as the ''Proclus' Paraphrase'' although its authenticity is questioned, being described as "very doubtful" by Professor Stephan Heilen.Heilen, Stephan, 'Ptolemy's Doctrine of the Terms and its Reception', in Jones (2010)
pp.62–63
The content of the ''Paraphrase'' is close to that of manuscripts of the ''Tetrabiblos'', but it uses simplified text with the aim of providing what Heilen calls "a more easily understandable version of the difficult original work". There is no modern critical edition of this text. The oldest extant manuscript is dated to the 10th century and housed in the
Vatican Library The Vatican Apostolic Library ( la, Bibliotheca Apostolica Vaticana, it, Biblioteca Apostolica Vaticana), more commonly known as the Vatican Library or informally as the Vat, is the library of the Holy See, located in Vatican City. Formally es ...
(Ms. ''Vaticanus gr.1453, S. X.'', ff.1–219). Some of the text of the ''Paraphrase'' was published with a Latin translation and Preface by
Philipp Melanchthon Philip Melanchthon. (born Philipp Schwartzerdt; 16 February 1497 – 19 April 1560) was a German Lutheran reformer, collaborator with Martin Luther, the first systematic theologian of the Protestant Reformation, intellectual leader of the Lut ...
in Basel, 1554, but this was not widely circulated. A full reproduction with an accompanying Latin translation was made around 1630 by the Vatican scholar
Leo Allatius Leo Allatius (Greek: Λέων Αλλάτιος, ''Leon Allatios'', Λιωνής Αλάτζης, ''Lionis Allatzis''; Italian: ''Leone Allacci, Allacio''; Latin: ''Leo Allatius, Allacius''; c. 1586 – January 19, 1669) was a Greek scholar, theolog ...
"for his own private gratification" and this was published by the Elzevir typsetters in
Leiden Leiden (; in English and archaic Dutch also Leyden) is a city and municipality in the province of South Holland, Netherlands. The municipality of Leiden has a population of 119,713, but the city forms one densely connected agglomeration w ...
, 1635, apparently without Allatius's knowledge or consent. Allatius' Latin translation was used as the source of all English translations of the ''Tetrabiblos'' prior to the Robbins' edition of 1940. These include translations made by John Whalley (1701); the Whalley "corrected edition" made by
Ebenezer Sibly Ebenezer Sibly (1751 – 1799) was an English physician, astrologer and writer on the occult. Life He was the son of Edmund Sibly and Mary Larkholm, born in the parish of Cripplegate ward, London. He was the brother of Manoah Sibly. Early ...
and his brother (1786); J.M. Ashmand (1822); James Wilson (1828); and other 19th-century privately circulated manuscripts such as that of John Worsdale.


Greek manuscripts

Although no copies of Ptolemy's original manuscript remain, there are other ancient works, such as Hephaistio's ''Apotelesmatics I'', which describe or reproduce some of its passages. These have been used to help verify disputed areas of content. The oldest fairly complete Greek manuscript of the text (rather than the paraphrased edition made of it) is dated to the 13th century. Two or three others are dated to the 14th century but most are dated to the 15th and 16th centuries. In the 'Introduction' to his 1940's translation, Frank Eggleston Robbins reported the existence of at least 35 manuscripts containing all or a large part of the ''Tetrabiblos'' in European libraries. Robbins (1940) 'Translator's Introduction
p.xxiii
The first printed edition was made in 1535 with an accompanying Latin translation by the German classical scholar
Joachim Camerarius Joachim Camerarius (12 April 150017 April 1574), the Elder, was a German classical scholar. Life He was born in Bamberg, in the Prince-Bishopric of Bamberg. His family name was Liebhard, but he was generally called Kammermeister, previous member ...
. This was reprinted in 1553 and is "notable for offering the first Latin translation based upon a Greek rather than Arabic source". Robbins noted the page numbers of the 1553 edition in the Greek text which faces his English translation, stating "My collations have been made against Camerarius' second edition, because thus far this has been the standard text and it was most convenient". Also in 1940, a Greek critical edition was published by Teubner, in Germany, based on the unpublished work of Franz Boll which was completed by his student Emilie Boer. Robbins expressed regret at not being able to refer to this in the preparation of his English translation. In 1994 the 'Boll-Boer' edition became the basis of a serialised English translation by Robert Schmidt, published by Project Hindsight. The 'Translator's Preface' was critical of Robbins' understanding of some of the "conceptual issues involved" and argued the need for a new English translation which recognised the "probable superiority of the Teubner text edited by Boll and Boer in 1940". The most recent critical edition of the Greek text was made by the German scholar Professor Wolfgang Hübner, and published by Teubner in 1998. Based on 33 complete and 14 partial manuscripts, Hübner also incorporated the unpublished notes of Boer and the reasoning given in the Robbins and Boll-Boer editions. This is now considered the authoritative edition. A reviewer's comment in The ''Classical Review'' declares of it "Progress over previous editions is evident on virtually every page".


Associated texts


Commentary

In addition to the Arabic commentary on the ''Tetrabiblos'' made by Ali ibn Ridwan (Haly) in the 11th century, Grafton (1999)br>pp.136–7
significant attention is given to an anonymous Greek ''Commentary'', which has older, obscure origins. It was written at an uncertain date, in either late antiquity or the
Byzantine The Byzantine Empire, also referred to as the Eastern Roman Empire or Byzantium, was the continuation of the Roman Empire primarily in its eastern provinces during Late Antiquity and the Middle Ages, when its capital city was Constantinopl ...
period. This is also attributed to Proclus, as the presumed author of the ''Paraphrase'', although Heilen has remarked that such an attribution "looks like guesswork".Heilen, Stephan, 'Ptolemy's Doctrine of the Terms and its Reception', in Jones (2010)
pp.65–66
Houlding has also pointed out that differences in tabulated information presented within the ''Paraphrase'' and the ''Commentary'' "is a telling argument that both cannot be the work of the same author". The Greek ''Commentary'' was first printed in 1559 with an accompanying Latin translation by
Hieronymus Wolf Hieronymus Wolf (13 August 1516 – 8 October 1580) was a sixteenth-century German historian and humanist, most famous for introducing a system of Roman historiography that eventually became the standard in works of medieval Greek history. Lif ...
. This claimed to be based on a heavily corrupted manuscript which required numerous conjectures by a scholarly friend of Wolf, who preferred to remain anonymous rather than face reproaches for "dabbling in this sort of literature". Wolf's edition was bound with an ''Introduction to the Tetrabiblos'', attributed (speculatively) to Porphyry, and the
scholia Scholia (singular scholium or scholion, from grc, σχόλιον, "comment, interpretation") are grammatical, critical, or explanatory comments – original or copied from prior commentaries – which are inserted in the margin of t ...
of Demophilus. The purpose of the ''Commentary'' was to offer demonstrated illustrations and fuller explanation of the astrological principles described by Ptolemy. Following Wolf's edition, large passages were incorporated into Latin astrological works which featured extensive collections of example horoscopes. Two notable examples are
Jerome Cardan Gerolamo Cardano (; also Girolamo or Geronimo; french: link=no, Jérôme Cardan; la, Hieronymus Cardanus; 24 September 1501– 21 September 1576) was an Italian polymath, whose interests and proficiencies ranged through those of mathematician, ...
's ''Ptolemaei De Astrorvm Ivdiciis'' (Basel, 1578) and Francisco Junctinus's ''Speculum Astrologiae'' (Lugduni, 1583). Modern translators continue to make reference to the Hieronymous Wolf ''Commentary'' in their explanatory annotations.


Centiloquium

The ''
Centiloquium The ''Centiloquium'' (= "one hundred sayings"), also called ''Ptolemy's Centiloquium'', is a collection of one hundred aphorisms about astrology and astrological rules. It is first recorded at the start of the tenth century CE, when a commentary ...
'' 'one hundred (sayings)' was the common Latin title of a collection of 100 important astrological
aphorism An aphorism (from Greek ἀφορισμός: ''aphorismos'', denoting 'delimitation', 'distinction', and 'definition') is a concise, terse, laconic, or memorable expression of a general truth or principle. Aphorisms are often handed down by ...
s. It was also known in Latin as ''Liber Fructus'' (Arabic: ''Kitab al-Tamara''; Hebrew: ''Sefer ha-Peri'') 'Book of the Fruit'. Sela (2003)br>pp.321–2
The latter reflected the belief that this offered a summation of Ptolemy's key astrological principles, and therefore presented "The Fruit of his Four Books". Houlding (2006)br>'Introduction'
It began, as all Ptolemy's works did, with a dedication to "Syrus", which helped support the assumption of the work's Ptolemaic authenticity. Early manuscripts were commonly accompanied by a commentary on their use authored by
Ahmad ibn Yusuf al-Misri Abu Ja'far Ahmad ibn Yusuf ibn Ibrahim ibn Tammam al-Siddiq Al-Baghdadi ( ar, أبو جعفر أحمد بن يوسف بن ابراهيم بن تمام الصديق البغدادي; 835–912), known in the West by his Latinized name Hametus, was ...
(835–912). This became translated into Latin at the same time as translations were being made of the Arabic editions of the ''Tetrabiblos''. The earliest translations were made by Johannes Hispanensis in 1136 and
Plato of Tivoli Plato Tiburtinus ( la, Plato Tiburtinus, "Plato of Tivoli"; fl. 12th century) was a 12th-century Italian mathematician, astronomer and translator who lived in Barcelona from 1116 to 1138. He is best known for translating Hebrew and Arabic docum ...
in 1138. Ali ibn Ridwan (Haly), who had produced the Arabic commentary on Ptolemy's work, noticed that the aphorisms highlighted principles of interrogational astrology, and wondered why Ptolemy had not included coverage of these themes in his ''Tetrabiblos''. Jerome Cardan was the first to declare the work a forgery based on such differences, referring in his commentary on the ''Tetrabiblos'' to an argument of
Galen Aelius Galenus or Claudius Galenus ( el, Κλαύδιος Γαληνός; September 129 – c. AD 216), often Anglicized as Galen () or Galen of Pergamon, was a Greek physician, surgeon and philosopher in the Roman Empire. Considered to be o ...
: "In the old days, kings who were trying to establish great libraries bought the books of famous men at very high prices. By doing so they caused men to ascribe their own works to the ancients". The authorship of the text is now ascribed to "Pseudo-Ptolemy". Some scholars suggest that Ahmad ibn Yusuf was its true author. Others believe that the ''Centiloquium'', though not Ptolemy's, may preserve some collation of authentic materials from
Hellenistic astrology Hellenistic astrology is a tradition of horoscopic astrology that was developed and practiced in the late Hellenistic period in and around the Mediterranean Basin region, especially in Egypt. The texts and technical terminology of this tradition ...
. Houlding (2006)br>'Introduction'
Tester (1987) p
154–5
Ultimately, the historical assumption that the ''Centiloquium'' was part of Ptolemy's astrological legacy gave it widespread influence in the medieval period, by which it became established as an important text within the astrological tradition.


See also

*
Babylonian astronomy Babylonian astronomy was the study or recording of celestial objects during the early history of Mesopotamia. Babylonian astronomy seemed to have focused on a select group of stars and constellations known as Ziqpu stars. These constellation ...
– the ancient sources transmitted to Ptolemy *
Greek astronomy Greek astronomy is astronomy written in the Greek language in classical antiquity. Greek astronomy is understood to include the Ancient Greek, Hellenistic, Greco-Roman, and Late Antiquity eras. It is not limited geographically to Greece or to ...
– the astronomy of Ptolemy's era *
Ptolemy's world map The Ptolemy world map is a map of the world known to Greco-Roman societies in the 2nd century. It is based on the description contained in Ptolemy's book '' Geography'', written . Based on an inscription in several of the earliest surviving manu ...
– map of the ancient world as described by Ptolemy


Footnotes


Works cited

* * * * * * * * * * * * * * * * * * * * * * * * * * . * . * * * * * * * * * * * *


Further reading


Theoretical and Practical Astrology: Ptolemy and his Colleagues
by Mark Riley, 1974; ''Transactions of the American Philological Association'', 117, (Baltimore; London: Johns Hopkins University Press). Explores the difference of approach taken by Ptolemy to that of other contemporary astrologers.
Science and Tradition in the Tetrabiblos
by Mark Riley, 1988; ''Proceedings of the American Philosophical Society'', 132.1, (Philadelphia: American Philosophical Society). Considers the question of what Ptolemy contributed to astrology and why his work was so significant.


External links

;English language reproductions of the ''Tetrabiblos'' and associated texts

from ''Clavis Eliminata'' (1676); London: Josuah Coniers. Skyscript; retrieved 26 November 2011.

(1822); London: Davis and Dickson. Sacred Texts Archive; retrieved 16 November 2011.
James Wilson's translation ''Paraphrase''
(1828); London: William Hughes. Google Books; retrieved 16 November 2011.

(1940); Cambridge, Mass.: Harvard University Press; London: W. Heinemann. LacusCurtius; retrieved 16 November 2011.
Frank E. Robbins' translation of ''Tetrabiblos''
bound with W. G. Waddell's translation of Manetho's ''History of Egypt'' (1940). Cambridge, Mass.: Harvard University Press; London: W. Heinemann. Internet Archive, retrieved 16 November 2011. ;Greek and Latin reproductions of the ''Tetrabiblos'' and associated texts
Erhard Ratdolt, Venice, 1484
First printed Latin edition of ''Tetrabiblos'' based on Egidio Tebaldi's 13th-century Latin translation out of Arabic. Also includes the ''Centiloquium'' and ''Commentary'' by
Haly Abenragel Abū l-Ḥasan 'Alī ibn Abī l-Rijāl al-Shaybani ( ar, أبو الحسن علي ابن أبي الرجال) (commonly known as ''Haly'', ''Hali'', ''Albohazen Haly filii Abenragel'' or ''Haly Abenragel'', from ''ibn Rijal'') was an Arab astrolog ...
(Albohazen). Biblioteca Virtual del Patrimonio Bibliografico; retrieved 10 November 2011.
Bonetum Locatellum, Venice, 1493
Compemdium of Latin texts including the ''Tetrabiblos'', ''Centiloquium'', and Ali ibn Ridwan's ''Commentary''. Gallica Bibliothèque nationale de France; retrieved 20 November 2011.
Heirs of Octavius Scoti, Venice, 1519
Compendium of Latin texts including the ''Tetrabiblos'' and ''Centiloquium''. Universidad de Sevilla; retrieved 20 November 2011.
Johannes Hervagius, Basel, 1533
Latin edition based on Plato de Tivoli's translation. Warburg Institute; retrieved 19 November 2011.
Heinrich Petri, Basel, 1541
Latin edition containing Ptolemy's ''Almagest'', ''Tetrabiblos'', and the ''Centiloquium''. Biblioteca Virtual del Patrimonio Bibliografico; retrieved 19 November 2011.
Heinrich Petri, Basel, 1591
Latin reproduction of Hieronymous Wolf's translation the 'anonymous' ''Commentary'' attributed to Proclus. Biblioteca Virtual del Patrimonio Bibliografico; retrieved 19 November 2011.
Leo Allatius, Lugd. Batavorum, 1635
Greek and Latin translation of the 'anonymous' ''Proclus Paraphrase'' (''Procli Diadochi Paraphrasis'') based on manuscripts housed in the Vatican Library (oldest dates to 10th century: ''Codex Vaticanus Graecus'' 1453). Warburg Institute; retrieved 19 November 2011.
Emily Boer, Leipzig, 1961
Greek language edition of the ''Centiloquium'' published by Teubner. Open Library; retrieved 26 November 2011. ;Greek and Latin astrological works with substantial reference to the ''Tetrabiblos'' and the ''Commentary''
Jerome Cardan, Lyon, 1578
''Cl. Ptolemæi, de Astrorum Iudiciis'' (Latin). Herzog August Bibliothek Wolfenbuttel; retrieved 19 November 2011.
Francisco Junctinus, Basel, 1583
''Speculum astrologiae'' (Latin). Universad de Sevilla; retrieved 19 November 2011. {{Metaphysics Astrological texts Hellenistic astrology Western astrology 2nd-century books Books about the history of science Latin textbooks Cultural studies Natural philosophy Hellenistic philosophical literature