Why should anyone care about martyrdom in the contemporary world? Isn’t martyrdom merely a holdover from an earlier era, a malign inheritance from our more zealous and less reasonable ancestors? This chapter introduces the argument that martyrdom should be taken seriously not only as a concept from history but also as a consequential social action in the contemporary world. The influence of martyrdom in the modern world is perhaps most strikingly seen in the rise of global Islamist terror campaigns. Yet this chapter asks that we consider martyrdom as a core concept in the Western European political and religious experience. Throughout history, communities have used the commemoration of violent death to cultivate stories of ultimate sacrifice. These stories have practical consequences to the extent that they generate sympathy and support from the public. But these stories can also offer a unique prism through which to view and interpret history. As a form of commemorated sacrifice, martyrdom condenses bitter cultural and historical conflicts to a comprehensible scale. Given this, a comparison of cases of martyrdom across time can develop a new perspective on macro-historical social change. This chapter concludes by arguing that a historical comparison of cases of martyrdom is particularly suited to analyzing macro-historical changes involving two distinct phenomena: secularization and sovereignty.