> be evidence of periodic burning of villages because that's what warlords do to peaceful settlements Not really. Look at "pax Romana" or Aztecs. Warlords brin

> be evidence of periodic burning of villages because that's what warlords do to peaceful settlements Not really. Look at "pax Romana" or Aztecs. Warlords bring peace! If villages are part of the same empire, they are at peace. Without central force there is constant local bickering and fight. Warlords take their tributes (including soldiers) and wage war far away. Or they punish population by killing one man in family. There is no need to burn entire village, it hurts profit. People at that time were able to build huge megalithic structures. It is safe to assume they could organise small army of a few thousands (enough to dominate 20k settlements).