 Leibniz had corresponded with Arnauld some fifteen years earlier, in connection with Leibniz’s efforts to reunite the Christian churches. These efforts took a new turn in March, 1672, when Leibniz, then just 25 years old, left Mainz for Paris on a secret political mission for his patron, Baron Johann Christian von Boineburg, who was in turn minister to Johann Philipp von Schönborn, the Elector of Mainz. Both men were converts from Lutheranism to Catholicism. Leibniz’s diplomatic mission was a failure, but he had other reasons for wanting to visit Paris. He was eager to enter into the brilliant intellectual life of the French capital, and he stayed there, with a brief sojourn in England, until 1676, making the acquaintance of a number of leading intellectuals. During this time, he undertook for the first time the serious study of mathematics. But he also continued to work toward a philosophical position that he hoped would help reunify the churches.