The theme of ethnicity in the ancient Greek world has been a popular subject of investigation in terms of both the historical development of Greek identity and its literary treatment in particular works or genres especially of the classical period. Following major historical and cultural developments, key texts of fifth-century literature and especially Attic drama extensively explore the Greek-barbarian distinction in ways that appear to be morally charged, and have hence been read as testimonies to the idea of Greek superiority over the Foreigner and especially the Easterner. However, a close reading of the most seminal works of the period suggests that this increased interest in the Greek-barbarian opposition assumes the form of a vigorous exploration of its various aspects or contradictions, which systematically problematises this opposition on three levels: conceptual, factual, and ethical.