Gilgamesh was an historical king of Uruk in Babylonia, on the River Euphrates in modern Iraq; he lived about 2700 B.C. Although historians (and your textbook) tend to emphasize Hammurabi and his code of law, the civilizations of the Tigris-Euphrates area, among the first civilizations, focus rather on Gilgamesh and the legends accruing around him to explain, as it were, themselves. Many stories and myths were written about Gilgamesh, some of which were written down about 2000 B.C. in the Sumerian language on clay tablets which still survive; the Sumerian language, as far as we know, bears no relation to any other human language we know about.