People whose cultures didn’t value them/were disconnected from the original creators eg. Egypt
People who ran empires and were just going to destroy them for a new palace or something anyway eg. Ottomans in Greece
People who were forced to give them up in the face of a much stronger miltary power eg. a lot of the Chinese & Indian stuff
I don’t think there’s anything unethical about keeping 1 and 2 as they wouldn’t exist otherwise, but 3 should be returned and replaced with other items from the collection or replicas
One of three:
I don’t think there’s anything unethical about keeping 1 and 2 as they wouldn’t exist otherwise, but 3 should be returned and replaced with other items from the collection or replicas