This chapter explores two ideologies, communism and nationalism, with reference to two countries Germany and Vietnam. It begins by tracing some of the conceptual difficulties in reconciling communism and nationalism and how these were addressed in practice. By helping to repudiate communism in contemporary Germany and consolidate it in Vietnam, museums make a significant contribution to shaping nation-building in each case. Differing conceptions of the museum's role in socialist and capitalist, contemporary and traditional settings provide the context for a comparative analysis of the German Historical Museum in Berlin and the Vietnamese History Museum in Hanoi. Germany and Vietnam's national history museums help to propagate a nation-building ideology through myths of longue durée and national unity. In performing a legitimating function for soldered states, the museums create a link between ancient artefacts and contemporary communities, which also has wide-ranging implications for collectors and curators.