text: When Frederick ascended the throne in 1740, he reinstituted the Prussian Academy of Sciences (Berlin Academy), which his father had closed down as an economy measure. Frederick's goal was to make Berlin a European cultural centre that rivalled London and Paris. He invited intellectuals from across Europe to join the academy, made French the official language and made speculative philosophy the most important topic of study. The membership was strong in mathematics and philosophy and included Immanuel Kant, 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, director of the Berlin Academy from 1746 to 1759 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 approach and emphasised the international Republic of Letters as the vehicle for scientific advance. By 1789, the academy had gained 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 centre for mathematical research. Other intellectuals attracted to the philosopher's kingdom were Francesco Algarotti, d'Argens, and Julien Offray de La Mettrie.