Adaptation

Adaptation is a Special power which allows priests to convert enemy Settlements and Town Centers and gain part of the owner's sett/TC's Civilization. Special powers are taken first, then civ upgrades are random chosen from the owner on till you have everything he has (this will require more sett/TC conversions, which will be difficult since your enemy will start to build Universities nearby)

It's common in Citybuilder games for one person to 'buy' settlements from other players for something in return.

It's also useful for checking saved games for hexed civilizations.