The proposed conference will complement activities underway in Comparative Ethics of War (CEW), a RCN funded project at PRIO. The project leader, Gregory Reichberg, is a specialist in the Just War tradition of Roman Catholicism. As part of CEW, he is writing a monograph on Peace and War in the thought of St. Thomas Aquinas (1225–1274). Hence, under his direction a conference has been convened to examine how the Just War idea, of which Thomas Aquinas was one of the original proponents, has undergone transformation in the Roman Catholic tradition. The conference output will be an edited volume, with state-of-the-art presentations on contemporary Catholic thought regarding war and ethics.