As the origin story of the present world political order the globalization of international society serves as a unifying frame for the discipline of international relations. This paper considers the consequences of the shift from the ‘expansion’ to the ‘globalization’ of international society in relation to two main texts: Hedley Bull's The Anarchical Society and Tim Dunne and Christian Reus-Smit's The Globalization of International Society. The analysis shows that Bull's conception of world order depends on a key distinction between aggregate and system which marks the difference between an aggregate of local political orders and a systematically unified world political order (a global international system). Because recent histories of the globalization of international society remain guided by Bull's distinction, they are unable to explain this transition in historical terms without transforming the global international order from the explanandum of the globalization of international society to its explanans. As a result, global histories of the globalization of international society grant a global international system a structural permanence the original expansion story was meant to contest. In doing so they change profoundly the kind of questions that can be asked regarding the origins, character, and future of political order on earth.