St. Augustine’s efforts to reconcile Christ’s teaching with the requirements of statecraft led him to became the founder of a theory of comparative justice we now call just war. Just war was designed to limit the nature and scope of imperial Roman warfare. Post-Constantine Christian attitudes to the use of organised political violence have largely been interpreted and guided by this tradition. Over time the term just war has been expanded beyond its specifically Christian component to represent the dominant Western line of moral thinking on war. The key issue in this paper is to review the common conceptual vocabulary that unites just war theorists and claims Augustine as its key progenitor