The world’s first experiment in tribal federalism.
It’s probably the oldest documented one, the Elamites didn’t seem inclined to that, satisfied themselves with pulverizing rival city-states and carrying off their idols, back to their own capital.
Probably anything older than the Assyrian forced migration took the form of enslavement.
The Assyrians also imposed tribute, which typically amounted to the cost of having kicked the asses of the vanquished in the first place. The harder they resisted, the longer it took, the more it cost, the higher the tribute. And after the Assyrians left town, if the cost was high and their economy in a shambles, they’d refuse to pay, leading to another Assyrian force the next year.