Taking the phenomenon of empire as its starting point, this article seeks to provide a framework for addressing the question of how and why international systems change over time. Synthesising elements from network-relational analysis and practice theory, I argue that international systems are best thought of as being composed of multiple partially overlapping and interrelated hierarchical networks. These networks are made up of social ties – as in classic network analysis – but also of specific repertoires of practice. Systemic transformations happen through the reconfiguration of networks, both through shifts in social ties and through changes in their practices. Empire provides a particularly illuminating window into the topic of systemic change, in part because a major driver of historical transformations has been the expansion of empires and their encounters with other heterogeneous polities across the globe, and in part because a focus on imperial interactions highlights the limitations of existing unit-centric perspectives. Drawing on examples from the nineteenth century, I illustrate the usefulness of the framework by showing how different regionally anchored systems came into contact with the expanding spheres of Western empires and how such points of interaction contributed to the development of an increasingly global international system.