  From 1906 to 1913, Duhem delved deeply into his favorite guide for the recovery of the past, the scientific notebooks of Leonardo de Vinci. He published a series of essays uncovering de Vinci’s medieval sources and their influences on the moderns. The third volume of Duhem’s Etudes sur Léonard de Vinci gained a new subtitle, Les précurseurs parisiens de Galilée, announcing Duhem’s bold new thesis that even the works of Galileo had a medieval heritage; reviewing his historical accomplishments, Duhem summarized them as follows: