AbstractProducing a means of conceptualising and analysing international society as an assemblage, this article reflects on Adam Watson’s Evolution of International Society and demonstrates how an assemblage theory approach allows us to undertake Watson’s general aims to engage in broad, comparative analyses of international societies historically and produce a history of contemporary international society, but without the problematic biases and omissions that plague the empirical dimensions of his work. Understanding international society as an assemblage affords an ability to see that the endurance of so much of Western European international society in contemporary, global international society is owing to its particular form of assemblage. As a highly adaptive form of assemblage, what changes there might be in the international domain tend to occur within the assemblage, as the assemblage’s form renders both a substantive change of the assemblage and the establishment of any rival assemblage unlikely.