A gift between former enemy tribes?
They found the FEDEX receipt...
Trade, or war booty, my guess is, the former.
In ancient Mesopotamia, city-states would carry off the main idol of a defeated rival city and display it as a subject to their own main idol. If this altar stone was carried off due to war, it could be something like that.
The Stone of Scone (’skoon’) was used for a few centuries as the place where the kings of Scotland were crowned. Probably an earlier succession of other stones had served that purpose prior to that. In the 1950s Scot separatists cut the stone out from under the throne used during UK coronations since the 17th century. The stone had been carried off in the late 13th century and used for English, then UK coronations thereafter. While trying to rely on the Old Gray Cranium, I wound up loading the wikipedia page on this, and it’s pretty fascinating, btw.
Superstition — Stevie Wonder
https://www.youtube.com/watch?v=7_tmeHCO1IM