After The Fall: Why do Some Societies Rise Again From The Ashes? After decades of studying how societies end and begin, archaeologists have turned their attention to a poorly understood intermediate step: what happens after collapse. ... Studies in Peru, for instance, suggest that the Inca rose to power in the 15th century partly by learning important lessons from nearby empires that had collapsed not long before. In Syria, researchers have found that a loose tribal structure allowed early civilizations there, in the third millennium B.C., to regenerate more readily than they might have under strict leadership. And in Cambodia, archaeological findings suggest that the Khmer empire sustained itself from 500 B.C. to A.D. 1250 by closely linking each group's rise with the traditions of the previous rulers. -- via Ghost of a Flea

The ideological strategy mentioned for the Khmer -- claiming descent from a previous mighty civilization -- is quite common. The Incas played off the heritage of Tiahuanaco. Every European conqueror from Charlemagne to Musolini claimed to be resurrecting Rome (and political theorists with as un-imperial a vision as Rousseau still paid homage to the Roman example). The strategy seems to draw on two ideas. On the one hand, it frames the former empire as the "normal" or base state of things, so that the rise of the new empire is less a building and more a reclaiming of what is rightfully so. Second, it seems to serve as a model or teacher and a proof that the quest can be achieved. This second sense is especially apparent in the mirror image process among non-imperial cultural movements (such as Daniel Quinn's praise of pre-agricultural environmental ethics or Goddess theorists' vision of a prehistoric "matriarchy").