This paper argues that in his discussions of the ethics of sovereignty, Christian Thomasius makes use of two very different conceptions of the prince's moral persona. In his natural law works, Thomasius draws on a Christian-Epicurean moral anthropology, in order to model a sage–prince whose capacity to rule is conditioned by his capacity for restraint of the passions. In his works in the area of Staatskirchenrecht or constitutional church law, however, Thomasius adopts a different stance. Here, drawing on Pufendorf's construction of multiple moral personae, Thomasius restricts the ethic of passional restraint to the personae of the ‘man’ and the Christian, drawing the duties of the prince from a quite different source: the goal of preserving social peace through the exercise of a coercive sovereign power. It is argued that these different kinds of political ethic are associated with the different purposes of Thomasius's natural-law and staatskirchenrechtlich writings, the former being dedicated to the mor...