As far as we know, the Sumerians were the first high civilized people in the world.  For a long time it was thought the Semitic languages were the earliest, and then Sumerian is discovered and for a long time the scholars were saying, “Well, this was just the secret language of the Semitic priests.”  They had a hard time giving that one up, but finally they had to.  Sumerian was related neither to Semitic nor to the Indo-European languages.   G77

One of the oldest recorded hero journey tales - possibly predating Gilgamesh - is the Sumerian myth of the sky goddess Inanna's descent to the netherworld.  The Descent of Inanna was inscribed on an epic poem on tablets dating from around 1750 B.C.; they lay buried for close to 4,000 years in the ruins of Nippur, Sumer's cultural and spiritual center.   G 83