Leonardus Lessius' Views on Heresy, War, and Rebellion

This article aims to analyse the opinions and moral resolutions of the Jesuit scholar Leonardus Lessius (1554-1623), one of the leading moral theologians from the Southern Netherlands, with regard to three hotly debated issues of his time: heresy, war, and the act of rebellion. I begin with a discussion of Lessius’ monumental treatise De iustitia et iure (1605), which provided a comprehensive Thomistic commentary on various subjects pertaining to the four cardinal virtues. Next, I focus on his posthumously published Casus Conscientiae (1645), which dealt with practical ethical cases and dilemmas and offered manageable solutions to these problems. Lastly, I examine one of Lessius’ commentaries on the Secunda secundae of Thomas Aquinas’ Summa theologica, in which he explained his views on just and unjust war. Through a combined study of these works, I aim to illustrate that Lessius not only provided his advisees with a moral framework to guide their actions, but that he also argued for a broader vision of politics as an art of making morally sound decisions.