Every piece of land, except for a very few in the deepest Amazon, have had visitors from other lands and these visitors either leave, because there was nothing of worth to claim, or were driven out by people who had already claimed the land and were willing to fight for it, or they killed the people living on the land and took their resources, or they moved in and lived with the people that were already living on the land.

Humanity has always existed in a state of impermanence.  Someone from far away might come and try to take your stuff and your land, or lo and behold it might be the tribe next door.  For anyone to act as if any occupation of land and resources has any kind of permanence is being naive.