Sumerians. Or, as they named themselves, the black-headed people.
Archaeological evidence suggests this civilization was humanity’s first. Records like the Sumerian King List (AKA the Chronicle of the One Monarchy) show that the Sumerians on some level agreed. Setting aside the cynical distinction between monarchs and peasants, leaders and led, etc., there is evidence that they viewed themselves as the first people, created and placed on Earth by the god Enki.
But, you might say, most cultures...
