Abstract
The focus of this paper is a suite of Latin papers from 1685, some of which are still unpublished, in which Leibniz writes in the guise of a Catholic in order to defend Catholicism and counter Protestant objections, and this despite him being a lifelong Lutheran. After providing an overview of these writings (which I refer to as Leibniz’s “Catholic” writings) and the grounds for dating them to May–June 1685, I consider their purpose, arguing against the claim that they were intended to support Church reunion and suggesting instead that they were apologetic in nature, intended as a reactivation or reimagining of Leibniz’s earlier “Catholic Demonstrations” project. I identify the patron Leibniz had in mind for these writings as Landgrave Ernst von Hessen-Rheinfels and support this by a detailed comparison of the “Catholic” writings with the Leibniz-Landgrave correspondence and the Landgrave’s still-unpublished essays. This reveals that the Protestant arguments Leibniz uses in the “Catholic” writings are the very ones that he himself used when writing to the Landgrave, and that the responses Leibniz gives to these arguments are the very ones that the Landgrave used. I also consider the context of the writings, suggesting they were crafted during a period of personal uncertainty for Leibniz and possibly aimed at securing a position under the Landgrave.