Unlike many other social sciences, international relations (IR) spend relatively little time assessing the impact of the nineteenth century on its principal subject matter. As a result, the discipline fails to understand the ways in which a dramatic reconfiguration of power during the "long nineteenth century" served to recast core features of international order. This article examines the extent of this lacuna and establishes the ways in which processes of industrialization, rational state-building, and ideologies of progress served to destabilize existing forms of order and promote novel institutional formations. The changing character of organized violence is used to illustrate these changes. The article concludes by examining how IR could be rearticulated around a more pronounced engagement with "the global transformation."