 Before coming to Paris, he had discussed the project of reunifying the churches with his patron Boineburg, and had corresponded with Arnauld, in 1671, about the Eucharist, proposing an account of the real presence that he thought would be acceptable to both Lutherans and Catholics. But it was Leibniz’s interest in theodicy and related problems about justification that flourished in Paris. There, in 1673, he composed Confessio Philosophi, a dialogue in Latin between a theologian and a philosopher that is sometimes referred to as “his first theodicy.” Thirty-seven years later in the Theodicy, Leibniz says,