SummaryInternational intellectual history—the intellectual history of the international and an internationalised intellectual history—has recently emerged as one of the most fertile areas of research in the history of ideas. This article responds to eight essays inspired by my own contribution to this field in Foundations of Modern International Thought. It engages with their positive achievements regarding the recovery of other foundations for modern international thought: for example, in theology, historiography and gender history. It addresses some of the methodological problems arising (...) from the search for foundations, notably anachronism, presentism and diffusionism. It expands on others' arguments about the international thought of Hobbes and Locke and the limits of cosmopolitanism. Finally, it points the way forward for international intellectual history as a collaborative, interdisciplinary, transnational and transtemporal enterprise. (shrink)