Sumer (Sumerian: 𒆠𒂗𒂠, ki-en-ĝir; "Name means::Land of the Lords of Brightness"; Akkadian: Shūmerū; Hebrew: שעיר, Shinʻār; "Land of the Rivers") was the earliest known civilization in the world located in southern Iraq, known as Mesopotamia.
Following the great flood in 2458BCE, people migrate - building ever larger communities. Mesopotamia accumulates and facilitates cultures and the infancy of new civilizations. Southern Mesopotamia specifically achieved great particular influence within the cities of Ur and Uruk. Influence continues to expand the presence of Mesopotamia and the Early Dynastic Period is accompanied through this dynamic growth culminating in the Sumerian Civilization consisting of city states organized around a temple and ruled by a priesthood.
Mesh-ki-ang-gasher is first King of Uruk followed by Enmerkar with Meskalamdug being recorded as first King of Ur succeeded by his son Akalamdug, and Akalamdug by his son Mesh-Ane-pada.  There is also the Akkadians to the north of what is roughly the region of Iraq, followed by centuries of cultural cohesion with the Sumerians of the more southern parts of Mesopotamia brings forth Sargon of Akkad.  Through the initiative of Sargon the worlds first empire was accomplished unifying the north (Akkad) and south (Sumer) parts of what was considered Mesopotamia. The Sargonic Empire lasted about one-hundred and fifty years until insurrection and invasion encouraging the mountain people called the Guti to come down from the mountain regions and attempt their rule in southern Mesopotamia for around a century.