Guido Bonatti (died between 1296 and 1300) was an Italian

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change. History On ...

astronomer 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 ...

and

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 ...

, who was the most celebrated

of the 13th century. Bonatti was advisor of

Frederick II, Holy Roman Emperor Frederick II (German: ''Friedrich''; Italian: ''Federico''; Latin: ''Federicus''; 26 December 1194 – 13 December 1250) was King of Sicily from 1198, King of Germany from 1212, King of Italy and Holy Roman Emperor from 1220 and King of Jer ...

, Ezzelino da Romano III,

Guido Novello da Polenta Guido II da Polenta (died 1330), also known as Guido Novello, was an Italian who served as lord of Ravenna from 1316 until 1322. The nephew of Lamberto I da Polenta, he acquired the lordship of the city after the latter's death. In 1316–1321 h ...

and

Guido I da Montefeltro Guido da Montefeltro (1223 – September 29, 1298) was an Italian military strategist and lord of Urbino. He became a friar late in life, and was condemned by Dante Alighieri in his ''Divine Comedy'' for giving false or fraudulent counsel. Bi ...

. He also served the communal governments of

Florence Florence ( ; it, Firenze ) is a city in Central Italy and the capital city of the Tuscany region. It is the most populated city in Tuscany, with 383,083 inhabitants in 2016, and over 1,520,000 in its metropolitan area.Bilancio demografico ...

Siena Siena ( , ; lat, Sena Iulia) is a city in Tuscany, Italy. It is the capital of the province of Siena. The city is historically linked to commercial and banking activities, having been a major banking center until the 13th and 14th centur ...

and

Forlì Forlì ( , ; rgn, Furlè ; la, Forum Livii) is a '' comune'' (municipality) and city in Emilia-Romagna, Northern Italy, and is the capital of the province of Forlì-Cesena. It is the central city of Romagna. The city is situated along the Vi ...

. His employers were all

Ghibellines The Guelphs and Ghibellines (, , ; it, guelfi e ghibellini ) were factions supporting the Pope and the Holy Roman Emperor, respectively, in the Italian city-states of Central Italy and Northern Italy. During the 12th and 13th centuries, r ...

(supporters of the

Holy Roman Emperor The Holy Roman Emperor, originally and officially the Emperor of the Romans ( la, Imperator Romanorum, german: Kaiser der Römer) during the Middle Ages, and also known as the Roman-German Emperor since the early modern period ( la, Imperat ...

), who were in conflict with the Guelphs (supporters of the

Pope The pope ( la, papa, from el, πάππας, translit=pappas, 'father'), also known as supreme pontiff ( or ), Roman pontiff () or sovereign pontiff, is the bishop of Rome (or historically the patriarch of Rome), head of the worldwide Cathol ...

), and all were excommunicated at some time or another. Bonatti's astrological reputation was also criticised in

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 ''

Divine Comedy The ''Divine Comedy'' ( it, Divina Commedia ) is an Italian narrative poem by Dante Alighieri, begun 1308 and completed in around 1321, shortly before the author's death. It is widely considered the pre-eminent work in Italian literature a ...

'', where he is depicted as residing in

hell In religion and folklore, hell is a location in the afterlife in which evil souls are subjected to punitive suffering, most often through torture, as eternal punishment after death. Religions with a linear divine history often depict hell ...

as punishment for his astrology. His most famous work was his ''Liber Astronomiae'' or 'Book of Astronomy', written around 1277. This remained a classic astrology textbook for two centuries.

Biography

Bonatti's dates of birth and death are unknown, the latter probably occurring between 1296 and 1300. In 1233 he is known as the winner of a dispute in

Bologna Bologna (, , ; egl, label= Emilian, Bulåggna ; lat, Bononia) is the capital and largest city of the Emilia-Romagna region in Northern Italy. It is the seventh most populous city in Italy with about 400,000 inhabitants and 150 different na ...

with the friar Giovanni Schio from

Vicenza Vicenza ( , ; ) is a city in northeastern Italy. It is in the Veneto region at the northern base of the ''Monte Berico'', where it straddles the Bacchiglione River. Vicenza is approximately west of Venice and east of Milan. Vicenza is a thr ...

, who maintained the non-scientific basis of astrology. He is probably the first

to have used the

midpoints in astrology A midpoint is a mathematical point halfway between two stellar bodies that tells an interpretative picture for the individual. There are two types of midpoints: direct and indirect. A direct midpoint occurs when a stellar body makes an aspect to th ...

. He used it to refine the timing for the military campaigns for the Count of

Montefeltro Montefeltro is a historical and geographical region in Marche, which was historically part of Romagna. It gave its name to the Montefeltro family, who ruled in the area during the Middle Ages and the Renaissance. Regions of Italy Overview Monte ...

Bonati announced to the count that he would repulse the enemy but would be wounded in the fray. The event transpired as Bonati had predicted, and the count, who had taken with him the necessary materials to staunch his wound in case the prophecy came true, became a devout adherent of astrology.Guido Bonati: Information and Much More from Answers.com
/ref> There is a tradition that Bonatti, towards the end of his life, took the friar's habit of the

Franciscan Order The Franciscans are a group of related Mendicant orders, mendicant Christianity, Christian Catholic religious order, religious orders within the Catholic Church. Founded in 1209 by Italian Catholic friar Francis of Assisi, these orders include t ...

. This has been contested, as Bonatti expressed great disdain for Franciscans in his early period. However, the Franciscan Order, in the 1924 inaugural issue of its annual publication, ''Franciscan Studies'', lays claim to Fra Guido Bonatti: According to the uncorroborated account of the Italian historian

Ludovico Antonio Muratori Lodovico Antonio Muratori (21 October 1672 – 23 January 1750) was an Italian historian, notable as a leading scholar of his age, and for his discovery of the Muratorian fragment, the earliest known list of New Testament books. Biography Bor ...

, Bonatti was murdered by robbers whilst returning from a study trip to Paris and other Italian cities, being set upon in or near Casena, with his body left upon the road. Evidence from various accounts establishes that Bonatti was in his eighties when he died.

References

External links

English translation of Bonatti's Liber Astronomiae
* ttp://www.skyscript.co.uk/bonatti.html The Life of Guido Bonattibr>"Anima astrologiae, Guido Bonatus by William Lilly, Student in Astrology"

Guidonis Bonati De Astronomia tractatus
(Latin)
Online Galleries, History of Science Collections, University of Oklahoma Libraries
High resolution images of works by Guido Bonatti in .jpg and .tiff format. {{DEFAULTSORT:Bonatti, Guido 13th-century births 1290s deaths People from Forlì Italian astrological writers Italian astrologers 13th-century astrologers 13th-century Italian mathematicians 13th-century Italian astronomers Court of Frederick II, Holy Roman Emperor