Scholars have long been interested in networks. Networks of scholarly exchange, trade, kinship, and patronage are some of the many such longstanding subjects of study. Recent and ongoing digital humanities projects are now considering networks with fresh approaches and increasingly complex datasets. At the heart of these digital projects are ‘network ontologies’ — functional data models for distilling the complicated, messy connections between historical people, objects, and places. Although scholars creating network ontologies necessarily focus on different types of content, if these networks are to form a coherent body of scholarship in the future, we must work towards the creation of interoperable ontological structures, rather than yet another set of competing standards. Here we examine the methodological considerations behind designing such interoperable ontologies, focusing primarily on the example of Early Modern historical networks. We argue that it would be infeasible to adopt a single ontological standard for all possible digital humanities projects; flexibility is essential to accommodate all subjects and objects of humanistic enquiry, from the micro-level to the longue-durée. However, we believe it possible to establish shared practices to structure these network ontologies on an ongoing basis in order to ensure their long-term interoperability
