Leo the Mathematician, the Grammarian or the Philosopher ( or ὁ Φιλόσοφος, ''Léōn ho Mathēmatikós'' or ''ho Philósophos''; – after January 9, 869) was a Byzantine philosopher and

logician Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the study of deductively valid inferences or logical truths. It examines how conclusions follow from premises based on the structure of arg ...

associated with the

Macedonian Renaissance Macedonian Renaissance () is a historiographical term used for the blossoming of Byzantine culture in the 9th–11th centuries, under the eponymous Macedonian dynasty (867–1056), following the upheavals and transformations of the 7th–8th c ...

and the end of the Second Byzantine Iconoclasm. His only preserved writings are some notes contained in manuscripts of

Plato Plato ( ; Greek language, Greek: , ; born BC, died 348/347 BC) was an ancient Greek philosopher of the Classical Greece, Classical period who is considered a foundational thinker in Western philosophy and an innovator of the writte ...

's dialogues. He has been called a "true

Renaissance man A polymath or polyhistor is an individual whose knowledge spans many different subjects, known to draw on complex bodies of knowledge to solve specific problems. Polymaths often prefer a specific context in which to explain their knowledge, ...

"Marcus Louis Rautman (2006), ''Daily Life in the Byzantine Empire'' (Greenwood Publishing Group, ), 294–95. and "the cleverest man in Byzantium in the 9th century". He was archbishop of Thessalonica and later became the head of the Magnaura School of philosophy in

Constantinople Constantinople (#Names of Constantinople, see other names) was a historical city located on the Bosporus that served as the capital of the Roman Empire, Roman, Byzantine Empire, Byzantine, Latin Empire, Latin, and Ottoman Empire, Ottoman empire ...

, where he taught

Aristotelian logic In logic and formal semantics, term logic, also known as traditional logic, syllogistic logic or Aristotelian logic, is a loose name for an approach to formal logic that began with Aristotle and was developed further in ancient history mostly b ...

Life

Leo was born in

Thessaly Thessaly ( ; ; ancient Aeolic Greek#Thessalian, Thessalian: , ) is a traditional geographic regions of Greece, geographic and modern administrative regions of Greece, administrative region of Greece, comprising most of the ancient Thessaly, a ...

, a cousin of the

Patriarch of Constantinople The ecumenical patriarch of Constantinople () is the archbishop of Constantinople and (first among equals) among the heads of the several autocephalous churches that comprise the Eastern Orthodox Church. The ecumenical patriarch is regarded as ...

, John the Grammarian. Little is known about his early life. In his youth he was educated at Constantinople, but found higher education options limited in the city and thus travelled to the monasteries of

Andros Andros (, ) is the northernmost island of the Greece, Greek Cyclades archipelago, about southeast of Euboea, and about north of Tinos. It is nearly long, and its greatest breadth is . It is for the most part mountainous, with many fruitful and ...

, where he could obtain rare manuscripts and was taught mathematics by an old monk. He originally taught privately in obscurity in Constantinople. The story goes that when one of his students was captured during the Byzantine–Arab Wars, the

Caliph A caliphate ( ) is an institution or public office under the leadership of an Islamic steward with Khalifa, the title of caliph (; , ), a person considered a political–religious successor to the Islamic prophet Muhammad and a leader of ...

al-Mamun was so impressed by his knowledge of mathematics, providing proofs that his own scholars were unable to complete, and predictive abilities that he offered Leo great riches to come to

Baghdad Baghdad ( or ; , ) is the capital and List of largest cities of Iraq, largest city of Iraq, located along the Tigris in the central part of the country. With a population exceeding 7 million, it ranks among the List of largest cities in the A ...

. Leo took the letter from the caliph to the

Byzantine emperor The foundation of Constantinople in 330 AD marks the conventional start of the Eastern Roman Empire, which Fall of Constantinople, fell to the Ottoman Empire in 1453 AD. Only the emperors who were recognized as legitimate rulers and exercised s ...

Theophilos, who, impressed by his international repute, conferred on him a school (''ekpaideutērion'') in either the Magnaura or the church of the Forty Martyrs. In the version of the story recorded by

Theophanes Continuatus ''Theophanes Continuatus'' () or ''Scriptores post Theophanem'' (, "those after Theophanes") is the Latin name commonly applied to a collection of historical writings preserved in the 11th-century Vat. gr. 167 manuscript.Kazhdan (1991), p. 2061 It ...

, the caliph, upon receiving Leo's letter of refusal, sent a letter requesting answers to some difficult questions of geometry and astrology, which Leo obliged. Al-Mamun then offered two thousands pounds of gold and a perpetual peace to Theophilos, if only he could borrow Leo's services briefly; the request was declined. The emperor then honoured Leo by having John the Grammarian consecrate him metropolitan of

Thessalonica Thessaloniki (; ), also known as Thessalonica (), Saloniki, Salonika, or Salonica (), is the second-largest city in Greece (with slightly over one million inhabitants in its metropolitan area) and the capital city, capital of the geographic reg ...

, which post he held from the spring of 840 to 843. There is a discrepancy in this account, however, in that the caliph died in 833. It has been suggested that either the connection between the caliph's final letter and Leo's appointment as metropolitan is in error, or the caliph in question was actually al-Mutasim. This latter option squares with the account of Symeon the Logothete, who makes Leo teach at the Magnaura from late 838 to early 840 and was paid handsomely. Leo, an iconoclast sometimes accused of paganism, lost his metropolitancy with the end of the

Iconoclasm Iconoclasm ()From . ''Iconoclasm'' may also be considered as a back-formation from ''iconoclast'' (Greek: εἰκοκλάστης). The corresponding Greek word for iconoclasm is εἰκονοκλασία, ''eikonoklasia''. is the social belie ...

in 843. Despite this, he delivered a sermon favourable of icons within months of Theophilos' death. Around 855, Leo was appointed at the head of a newly established Magnaura School by

Bardas Bardas (; died 21 April 866) was a Byzantine noble and high-ranking minister. As the brother of Empress Theodora, he rose to high office under Theophilos (. Although sidelined after Theophilos's death by Theodora and Theoktistos, in 855 he en ...

. He was renowned for his philosophical, mathematical, medical, scientific, literary, philological, seismological, astronomic, and astrological learning, and was patronised by

Theoktistos Theoktistos or Theoctistus (; died 20 November 855) was a leading Byzantine official during the second quarter of the 9th century and the ''de facto'' head of the regency for the underage emperor Michael III from 842 until his dismissal and ...

and befriended by

Photios I of Constantinople Photius I of Constantinople (, ''Phōtios''; 815 – 6 February 893), also spelled ''Photius''Fr. Justin Taylor, essay "Canon Law in the Age of the Fathers" (published in Jordan Hite, T.O.R., and Daniel J. Ward, O.S.B., "Readings, Cases, Mate ...

Cyril Cyril (also Cyrillus or Cyryl) is a masculine given name. It is derived from the Greek language, Greek name (''Kýrillos''), meaning 'lordly, masterful', which in turn derives from Greek (''kýrios'') 'lord'. There are various variant forms of t ...

was his student. Leo has been credited with a system of beacons (an optical telegraph) stretching across

Asia Minor Anatolia (), also known as Asia Minor, is a peninsula in West Asia that makes up the majority of the land area of Turkey. It is the westernmost protrusion of Asia and is geographically bounded by the Mediterranean Sea to the south, the Aegean ...

from

Cilicia Cilicia () is a geographical region in southern Anatolia, extending inland from the northeastern coasts of the Mediterranean Sea. Cilicia has a population ranging over six million, concentrated mostly at the Cilician plain (). The region inclu ...

to Constantinople, which gave advance warning of Arab raids, as well as diplomatic communication. Leo also invented several

automata An automaton (; : automata or automatons) is a relatively self-operating machine, or control mechanism designed to automatically follow a sequence of operations, or respond to predetermined instructions. Some automata, such as bellstrikers i ...

, such as trees with moving birds, roaring lions, and a levitating imperial throne. The throne was in operation a century later, when Liutprand of Cremona witnessed it during his visit to Constantinople. Records Liutprand's description.

Works

Most of Leo's writings have been lost. He wrote book-length works, poems, and many

epigrams An epigram is a brief, interesting, memorable, sometimes surprising or satirical statement. The word derives from the Greek (, "inscription", from [], "to write on, to inscribe"). This literary device has been practiced for over two millennia. ...

,Among them are some centos preserved in the Palatine Anthology; see Prieto Domínguez, Óscar (2011), ''De Alieno Nostrum: el Centón profano en el mundo griego''. Estudios Filológicos, 328. Salamanca: Ediciones Universidad de Salamanca. , p. 120-179. and was also a compiler, who brought together a wide range of philosophical, medical, and astronomic texts. His library can at least partially be reconstructed:

Archimedes Archimedes of Syracuse ( ; ) was an Ancient Greece, Ancient Greek Greek mathematics, mathematician, physicist, engineer, astronomer, and Invention, inventor from the ancient city of Syracuse, Sicily, Syracuse in History of Greek and Hellenis ...

Euclid Euclid (; ; BC) was an ancient Greek mathematician active as a geometer and logician. Considered the "father of geometry", he is chiefly known for the '' Elements'' treatise, which established the foundations of geometry that largely domina ...

, Paul of Alexandria,

Theon of Alexandria Theon of Alexandria (; ; ) was a Greek scholar and mathematician who lived in Alexandria, Egypt. He edited and arranged Euclid's '' Elements'' and wrote commentaries on works by Euclid and Ptolemy. His daughter Hypatia also won fame as a mathema ...

Proclus Proclus Lycius (; 8 February 412 – 17 April 485), called Proclus the Successor (, ''Próklos ho Diádokhos''), was a Greek Neoplatonist philosopher, one of the last major classical philosophers of late antiquity. He set forth one of th ...

, Porphyry,

Apollonius of Perga Apollonius of Perga ( ; ) was an ancient Greek geometer and astronomer known for his work on conic sections. Beginning from the earlier contributions of Euclid and Archimedes on the topic, he brought them to the state prior to the invention o ...

, the lost ''Mechanics'' of Quirinus and Marcellus, and possibly

Thucydides Thucydides ( ; ; BC) was an Classical Athens, Athenian historian and general. His ''History of the Peloponnesian War'' recounts Peloponnesian War, the fifth-century BC war between Sparta and Athens until the year 411 BC. Thucydides has been d ...

. He composed his own medical encyclopaedia. Later Byzantine scholars sometimes confused Leo with the scholar

Leo Choirosphaktes Leo Choirosphaktes, sometimes Latinized as Choerosphactes () and also known as Leo Magistros or Leo Magister, was a Byzantine official who rose to high office under Emperor Basil I the Macedonian () and served as an envoy under Emperor Leo VI the W ...

and the emperor

Leo VI the Wise Leo VI, also known as Leo the Wise (; 19 September 866 – 11 May 912), was Byzantine Emperor from 886 to 912. The second ruler of the Macedonian dynasty (although his parentage is unclear), he was very well read, leading to his epithet. During ...

, and ascribe to him

oracle An oracle is a person or thing considered to provide insight, wise counsel or prophetic predictions, most notably including precognition of the future, inspired by deities. If done through occultic means, it is a form of divination. Descript ...

Primary sources

Recent years have seen the first translations into English of a number of primary sources about Leo and his times. * Featherstone, Jeffrey Michael and Signes-Codoñer, Juan (translators). ''Chronographiae quae Theophanis Continuati nomine fertur Libri I-IV'' (Chronicle of

Books I-IV, comprising the reigns of

Leo V the Armenian Leo V the Armenian (, ''Léōn ho Arménios''; 775 – 25 December 820) was the Byzantine emperor from 813 to 820. He is chiefly remembered for ending the decade-long war with the First Bulgarian Empire, Bulgars, as well as initiating the second ...

Michael III Michael III (; 9/10 January 840 – 24 September 867), also known as Michael the Drunkard, was Byzantine emperor from 842 to 867. Michael III was the third and traditionally last member of the Amorian dynasty, Amorian (or Phrygian) dynasty. He ...

), Berlin, Boston: De Gruyter, 2015. * Kaldellis, A. (trans.). ''On the reigns of the emperors'' (the history of Joseph Genesios), Canberra: Australian Association for Byzantine Studies; Byzantina Australiensia 11, 1998. * Ševčenko, Ihor (trans.). ''Chronographiae quae Theophanis Continuati nomine fertur Liber quo Vita Basilii Imperatoris amplectitur'' (Chronicle of

comprising the Life of

Basil I Basil I, nicknamed "the Macedonian" (; 811 – 29 August 886), was List of Byzantine emperors, Byzantine emperor from 867 to 886. Born to a peasant family in Macedonia (theme), Macedonia, he rose to prominence in the imperial court after gainin ...

), Berlin: De Gruyter, 2011. * Wahlgren, Staffan (translator, writer of introduction and commentary). ''The Chronicle of the Logothete'', Liverpool University Press; Translated Texts for Byzantinists, vol. 7, 2019. * Wortley, John (trans.). ''A synopsis of Byzantine history, 811-1057'' (the history of

John Scylitzes John Skylitzes, commonly Latinized as Ioannes Scylitzes (, ; , ; early 1040s – after 1101), was a Byzantine historian of the late 11th century. Life Very little is known about his life. The title of his work records him as a '' kouropalat ...

, active 1081), Cambridge University Press, 2010.

Notes

Sources

* * *

References

External links

* Katerina Ierodiakonou and Börje Bydén (2008)
"Byzantine Philosophy."
''

Stanford Encyclopedia of Philosophy The ''Stanford Encyclopedia of Philosophy'' (''SEP'') is a freely available online philosophy resource published and maintained by Stanford University, encompassing both an online encyclopedia of philosophy and peer-reviewed original publication ...

''. {{DEFAULTSORT:Leo the Mathematician 790s births 9th-century deaths 9th-century Byzantine physicians 9th-century mathematicians Year of birth uncertain Year of death unknown Byzantine bishops of Thessalonica People from Thessaly 9th-century Byzantine writers 9th-century Byzantine scientists Byzantine astronomers 9th-century Greek philosophers 9th-century Greek mathematicians