Ancient country of western Asia, corresponding approximately to Babylonia of biblical times. The name “Sumer” probably dates from the early 3rd millennium BC. The first known leader was Etana, King of Kish (fl. c. 2800 BC), and successors enlarged the kingdom considerably. However, by the 23rd century BC Sumer had weakened and was invaded in turn by Sargon I the Great, the Gutians, the Amorites, and Hammurabi of Babylon, finally becoming part of the Babylonian Empire in the 18th century BC.