In this chapter I take a diachronic look into the ways in which the Graeco-Roman tradition tended to justify and reify the stereotypes concerning the East and its peoples from the Classical era to the Roman Imperial period. While most of the stereotypes about Eastern groups formed in response to interactions – either warlike or peaceful, sudden or slower – the theoretical explanation structures that were used to reify and explain these were most of the time entirely internal to the Graeco-Roman intellectual tradition. I will also try to offer a preliminary typology of the main strains of stereotypes that had the longest and most influential life within the ancient culturally shared pool of images, thereby combining some broader, theoretical observations with the interpretation of a selection of passages from the Classical to the Imperial era.