The Philosophy of Nature in the Middle Ages was the theme of the Third International Congress of Medieval Philosophy organized by the Societe Internationale pour l'Etude de la Philosophie Medievale, at Passo della Mendola in 1964. Peter Abelard composed this commentary in full knowledge of the monumental commentaries upon the Hexaemeronwritten by Basil of Caesarea and translated from Greek into Latin by Eustathius, by Ambrose of Milan, by Augustine of Hippo and also by Bede. The priority which Abelard gives to the historical sense in writing his commentary is not the least of the similarities he shows with the writing of Thierry of Chartres, his contemporary and, indeed, his teacher. There are many points of similarity between Thierry and Abelard as to the structure of the initial universe and the procession from formlessness to formation. Abelard’s work is most heavily influenced by the commentaries on Genesis by St Augustine.