The introduction identifies the framework of Catholic moral theology, which informs the specific approach of the authors in this special issue, as an important context to deepen the understanding of early modern just war discussions. Some of the most productive contributors to the debate in the sixteenth and seventeenth centuries were indeed Catholic moral theologians, who engaged with the question, driven by pastoral concerns over the conscience of subjects and rulers. The delegation of moral questions to theologians was an essential part of post-Tridentine Catholic culture which, however, eroded progressively in the seventeenth century as the tenets of moral theology as well as the external institutions of moral counsel attracted wide cri...