From Wikipedia

The History of Ancient Mesopotamia
Part Two

Mesopotamia has been home to many of the oldest major civilizations, entering history from the Early Bronze Age, for which reason it is often dubbed the "cradle of civilization". The rise of the first cities in southern Mesopotamia dates to the Chalcolithic (Uruk period), from ca. 5300 BCE; its regional independence ended with the Achaemenid conquest in 539 BCE. Mesopotamia was variously under Hellenistic, Persian, Mongol and Turkic rule, until gaining independence as Iraq in 1932.

The Fertile Crescent was inhabited by several distinct, flourishing cultures between the end of the last ice age (c. 10,000 BC) and the beginning of history. One of the oldest known Neolithic sites in Mesopotamia is Jarmo, settled around 7000 BC and broadly contemporary with Jericho (in the Levant) and Çatal Hüyük (in Anatolia). It as well as other early Neolithic sites, such as Samarra and Tell Halaf were in northern Mesopotamia; later settlements in southern Mesopotamia required complicated irrigation methods. The first of these was Eridu, settled during the Ubaid period culture by farmers who brought with them the Samarran culture from the north. This was followed by the Uruk period and the emergence of the Sumerians.

The Sumerians were firmly established in Mesopotamia by the middle of the 4th millennium BC, in the archaeological Uruk period, although scholars dispute when they arrived.

It is hard to tell where the Sumerians might have come from because the Sumerian language is a language isolate, unrelated to any other known language. Their mythology includes many references to the area of Mesopotamia but little clue regarding their place of origin, perhaps indicating that they had been there for a long time. The Sumerian language is identifiable from its initially logographic script which arose last half of the 4th millennium BC. Sumer is known as the Cradle of civilization.

By the 3rd millennium BC, these urban centers had developed into increasingly complex societies. Irrigation and other means of exploiting food sources were being used to amass large surpluses. Huge building projects were being undertaken by rulers, and political organization was becoming evermore sophisticated.

Throughout the millennium, the various city-states Kish, Uruk, Ur and Lagash vied for power and gained hegemony at various times. Nippur and Ngirsu were important religious centers, as was Eridu at this point. This was also the time of Gilgamesh, a semi-historical king of Uruk, and the subject of the famous Epic of Gilgamesh.

It is during this period that the potter's wheel was developed into the vehicular- and mill wheel.