The present study considers the sanctuary of Zeus at Olympia from the following two points of view: (1) How did interaction at the sanctuary contribute towards the drawing of an ethnic boundary between Hellenes and Barbarians and how was Hellenic athletic nudity construed in this context? (2) How did interaction at the sanctuary help the great multitude of Hellenic poleis to develop and maintain their identities as individual local communities? In this context particular emphasis is put on a consideration of the polis of Elis, the city-state which organised and staged the Olympic Games. The study argues that in the Classical period the sanctuary at Olympia was in fact one of the most important arenas in which the two most characteristic levels of Hellenic identity - the overall and shared Hellenic identity and the indiviual local polis-identity of each community - was negotiated, developed and maintained, and collects the evidence needed to substantiate these points.