Doesn't belong to anyone, the closest a person/group can come to owning a territory (or anything for that matter) is to claim it as theirs, still that doesn't mean it objectively belongs to them, deeds, proof of ownership don't mean anything when it comes down to it, it's just paper. No such thing as real ownership, it's just a concept, not a law of the universe.
Skyrim used to 'belong' to the Snow Elves until the Nedes came along and took it off them, the Nedes became the Nords and in true Narcissistic human nature actually convinced themselves that this is their undisputed land that is an extension of themselves and not it's own separate object with no real connection to them whatsoever, despite the fact that they had just hijacked Skyrim from someone else, they ironically refuse to accept the possibility that the same could happen to them at anytime and that their 'home' is essentially fair game to invaders strong enough to claim it, that's entitlement for you.
"I used to rescue presidents, then I took an arrow in the knee...and still rescued the president." -Snake Plissken