Imperial Frontier Processes
State ideologies were based on the notion that empires have no limits in their domination. However, imperial expansion often ended when a set of socioeconomic or geographic constraints were reached along the frontiers (Lattimore 1940; Whittaker 1994). Paradoxically, such frontiers also became the nexus of different forms of sociopolitical interaction that varied in magnitude and direction.
Ancient imperial frontiers were generally maintained through military force. However, maintaining a solid defensive front with large standing garrisons is often expensive. When sustained conflict was irregular and confrontations took the form of sporadic raids, the borders were efficiently protected with defense nodes at key locales (D’Altroy 1992; Hassig 1992; Luttwak 1976). With a minimum deployment of state investment, defense was more likely delegated to indigenous allies backed up by the promise of imperial support. In situations of marked peer polity competition, a common frontier policy was to pit the groups against one another to maintain control. This situation was also beneficial for competing factions as it provided them with the means to confront their own rivals while forming broader coalitions, and, ultimately, to challenge the empire (Barfield 2001; Bronson 1988; Hall 1991; Hassig 1988, 1992).