Had this assimilationist trajectory continued during the remainder of Voltaire’s life, his legacy in the history of Western philosophy might not have been so great. Yet during the 1750s, a set of new developments pulled Voltaire back toward his more radical and controversial identity and allowed him to rekindle the critical philosophe persona that he had innovated during the Newton Wars. The first step in this direction involved a dispute with his onetime colleague and ally, Pierre-Louis Moreau de Maupertuis. Maupertuis had preceded Voltaire as the first aggressive advocate for Newtonian science in France. When Voltaire was preparing his own Newtonian intervention in the Lettres philosophiques in 1732, he consulted with Maupertuis, who was by this date a pensioner in the French Royal Academy of Sciences. It was largely around Maupertuis that the young cohort of French academic Newtonians gathered during the Newton wars of 1730s and 40s, and with Voltaire fighting his own public campaigns on behalf of this same cause during the same period, the two men became the most visible faces of French Newtonianism even if they never really worked as a team in this effort. Like Voltaire, Maupertuis also shared a relationship with Emilie du Châtelet, one that included mathematical collaborations that far exceeded Voltaire’s capacities. Maupertuis was also an occasional guest at Cirey, and a correspondent with both du Châtelet and Voltaire throughout these years. But in 1745 Maupertuis surprised all of French society by moving to Berlin to accept the directorship of Frederick the Great’s newly reformed Berlin Academy of Sciences.