Gilgamesh has been known as the King of Heroes, the son of Lugalbanda and the goddess Ninsun. Gilgamesh was renowned far and wide for his strength and was quite possibly the basis for the myths of later demigod heroes. Gilgamesh seeks the Immortality of a full God but never achieves it.
Historically, there was a king of Uruk called Gilgamesh during the late 2nd millennium BC, but not much information is known about him.