Little is known of the life of Bernard of Verdun, except that he was a

Franciscan , image = FrancescoCoA PioM.svg , image_size = 200px , caption = A cross, Christ's arm and Saint Francis's arm, a universal symbol of the Franciscans , abbreviation = OFM , predecessor = , ...

friar A friar is a member of one of the mendicant orders founded in the twelfth or thirteenth century; the term distinguishes the mendicants' itinerant apostolic character, exercised broadly under the jurisdiction of a superior general, from the o ...

who may have been born in

Verdun Verdun (, , , ; official name before 1970 ''Verdun-sur-Meuse'') is a large city in the Meuse department in Grand Est, northeastern France. It is an arrondissement of the department. Verdun is the biggest city in Meuse, although the capital ...

and lived in the second half of the thirteenth century. His most significant work was the Treatise on the Whole of Astronomy (''Tractatus super totam astrologiam''), in which he defended Ptolemy's theory of epicycles and eccentrics against al-Bitruji's system of homocentric spheres. Contrary to the criticisms of

Averroes Ibn Rushd ( ar, ; full name in ; 14 April 112611 December 1198), often Latinized as Averroes ( ), was an Andalusian polymath and jurist who wrote about many subjects, including philosophy, theology, medicine, astronomy, physics, psych ...

and al-Bitruji, Bernard maintained that Ptolemy's theory was consistent with

Aristotle's Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatetic school of phi ...

physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which rel ...

. He further pointed out many technical inadequacies of al-Bitruji's model, and considered it to be insufficiently developed to challenge Ptolemy's system.Bernard of Verdun, "The Reality of Epicycles and Eccentrics Affirmed," pp. 520-24 in Edward Grant, ''A Sourcebook in Medieval Science,'' Cambridge: Harvard University Press, 1974

Notes

{{DEFAULTSORT:Bernard Of Verdun Medieval French astronomers