This has led to the suggestion that Gilgamesh himself really was a historical king of Uruk.Lugal-Zage-Si, the priest-king of Umma, overthrew the primacy of the Lagash dynasty, took Uruk, making it his capital, and claimed an empire extending from the Persian Gulf to the Mediterranean.The Akkadian word Shumer may represent this name in dialect, but we actually do not know why the Akkadians called the southern land Shumeru.
The Sumerians were a non-Semitic people and were at one time believed to have been invaders, as a number of linguists believed they could detect a substrate language beneath Sumerian.
However, the archaeological record shows clear uninterrupted cultural continuity from the time of the Early Ubaid period (5200-4500 cal BC) settlements in southern Mesopotamia.
Artifacts, and even colonies of this Uruk civilization have been found over a wide area - from the Taurus Mountains in Turkey, to the Mediterranean Sea in the west, and as far east as Central Iran.
The Uruk period civilization, exported by Sumerian traders and colonists (like that found at Tell Brak), had an effect on all surrounding peoples, who gradually evolved their own comparable, competing economies and cultures.
The date of this transition, from Ubaid 4 to Early Uruk, is in dispute, but calibrated radiocarbon dates from Tell Awayli would place it as early as 4500 calibrated), the volume of trade goods transported along the canals and rivers of southern Mesopotamia facilitated the rise of many large temple-centered cities where centralized administrations employed specialized workers.