The Ubaid period is marked by a distinctive style of fine quality painted pottery which spread throughout Mesopotamia and the Persian Gulf. During this time, the first settlement in southern Mesopotamia was established at Eridu (Cuneiform: NUN.KI), c. 5300 BC, by farmers who brought with them the Hadji Muhammed culture, which first pioneered irrigation agriculture. It appears that this culture was derived from the Samarran culture from northern Mesopotamia. It is not known whether or not these were the actual Sumerians who are identified with the later Uruk culture. Eridu remained an important religious center when it was gradually surpassed in size by the nearby city of Uruk. The story of the passing of the me (gifts of civilization) to Inanna, goddess of Uruk and of love and war, by Enki, god of wisdom and chief god of Eridu, may reflect this shift in hegemony.

Fine quality painted pottery is a distinctive style of what period in Sumerian history?