This article is concerned with the creation of the three national museums of Athens in the particuliar context of an emerging modern Greek national identity. These museums – the National Archaeological Museum, the Byzantine and Christian Museum and the Museum of Greek Folk Art – are studied here as institutions that carry on the national project. They have to elaborate and diffuse the historical continuity of the nation from ancient to modern times and its unicity, too. It is in this context that national museums use sciences (archaeology, history and folklore science) to support their objective. Their own policies perfectly illustrate the national will to hide problems of discontinuity and alterity. Lastly the authors present the results of a study made on a sample of visitors in order to determine how they perceived these three museums.