Before Frederick came to the throne in 1740, the Prussian Academy of Sciences was overshadowed by similar bodies in London and Paris. During the reign of Frederick's father, the Academy had been closed down as an economy measure, but Frederick promptly re-opened it when he took the throne in 1740. Frederick made French the official language and speculative philosophy the most important topic of study. The membership was strong in mathematics and philosophy and included Immanuel Kant, Jean D'Alembert, Pierre Louis de Maupertuis, and Étienne de Condillac. However the Academy was in a crisis for two decades at mid-century, due in part to scandals and internal rivalries such as the debates between Newtonianism and Leibnizian views, and the personality conflict between Voltaire and Maupertuis. At a higher level Maupertuis, the director 1746–59 and a monarchist, argued that the action of individuals was shaped by the character of the institution that contained them, and they worked for the glory of the state. By contrast d' Alembert took a republican rather than monarchical approach and emphasized the international Republic of Letters as the vehicle for scientific advance. By 1789, however, the academy had gained an international repute while making major contributions to German culture and thought. For example, the mathematicians he recruited for the Berlin Academy — including Leonhard Euler, Joseph-Louis Lagrange, Johann Heinrich Lambert, and Johann Castillon— made it a world-class center for mathematical research. Other intellectuals attracted to the philosopher's kingdom were Francesco Algarotti, d'Argens, and Julien Offray de La Mettrie. Immanuel Kant published religious writings in Berlin which would have been censored elsewhere in Europe.