 The Seleucid Empire was a major empire of Hellenistic culture that maintained the pre-eminence of Greek customs in which a Greek political elite dominated, in newly founded urban areas.The Greek population of the cities who formed the dominant elite were reinforced by emigration from Greece.The creation of new Greek cities were aided by the fact that the Greek mainland was overpopulated and therefore made the vast Seleucid Empire ripe for colonization.