None of the inhabitants of the world that Westeros is set on can say with certainty how old it is, nor how long the human race has lived on it. Different religions offer different supernatural origin myths for the human race, though it isn't clear which - if any - is correct. It is unknown if humans were literally created by supernatural forces, such as how the races in Tolkien's Middle-earth legendarium were created, or if they evolved from simpler life-forms as on real-life Earth (though the concept of biological evolution has never been developed by the inhabitants of Westeros's medieval setting).