History of Sumer
The history of Sumer, taken to include the prehistoric Ubaid and Uruk periods, spans the 5th to 3rd millennia BCE, ending with the downfall of the Third Dynasty of Ur around 2004 BCE, followed by a transitional period of Amorite states before the rise of Babylonia in the 18th century BCE.
The oldest known settlement in southern Mesopotamia is Tell el-'Oueili. The Sumerians claimed that their civilization had been brought, fully formed, to the city of Eridu by their god Enki or by his advisor (or Abgallu from ab=water, gal=big, lu=man), Adapa U-an (the Oannes of Berossus). The first people at Eridu brought with them the Samarra culture from northern Mesopotamia and are identified with the Ubaid period, but it is not known whether or not these were Sumerians (associated later with the Uruk period).
The Sumerian king list is an ancient text in the Sumerian language listing kings of Sumer, including several foreign dynasties. Some of the earlier dynasties may be mythical; the historical record does not open up before the first archaeologically attested ruler, Enmebaragesi (c. 2600 BCE), while conjectures and interpretations of archaeological evidence can vary for earlier events. The best-known dynasty, that of Lagash, is omitted from the kinglist.