The history of Sumer spans the 5th to 3rd millennia BCE in southern Mesopotamia, and is taken to include the prehistoric Ubaid and Uruk periods. Sumer was the region's earliest known civilization and ended with the downfall of the Third Dynasty of Ur around 2004 BCE. It was followed by a transitional period of Amorite states before the rise of Babylonia in the 18th century BCE.

The Uruk period existed from the protohistoric Chalcolithic to Early Bronze Age period in the history of Mesopotamia, after the Ubaid period and before the Jemdet Nasr period. Named after the Sumerian city of Uruk, this period saw the emergence of urban life in Mesopotamia and the Sumerian civilization. The late Uruk period saw the gradual emergence of the cuneiform script and corresponds to the Early Bronze Age; it has also been described as the "Protoliterate period".