This chapter traces how the concept of ethnicity emerged as a depoliticised alternative to nationality. By the end of the nineteenth century, the triumph of nationalism as the hegemonic source of state legitimacy had resulted in the politicisation of the nation concept. This conceptual linkage of ‘nation’ with ‘state’ opened up a terminological vacuum: If nationhood implied statehood, what label should be given to those stateless nations and national minorities that had neither a state of their own nor the political capacity to acquire one? Against this backdrop, the chapter traces how an embryonic concept of ethnicity was articulated to fill in the terminological void. The chapter’s empirical focus is on the early twentieth-century academic literature on nationalism and the establishment of the world’s first international minority rights regime after the First World War. The argument also has significant implications for debates surrounding the conceptual distinction between ‘civic’ and ‘ethnic’ nationalism.