The Seleucid state was in essence a military organization exacting tribute. Kingship was charismatic and intensely martial
(see KINGSHIP, HELLENISTIC). The monarchy’s heroic ethos required of the king to be a successful war leader able to defend the interests of his followers and the cities under his protection. Imperial ideology was universalistic, the self-presentation of the Seleucid monarch a continuation and elaboration of the age-old Near Eastern notion of a Great King.
Source: Academia.edu