L. W. King, A History of Sumer and Akkad
“ In an earlier age the twin kingdoms of Ur and Erech had dominated southern Babylonia, and their rulers had established the kingdom of Sumer, which took an active part in opposing the advance of Semitic influence southwards. The subjection of Sumer by the Dynasty of Akkad put an end for a time to all thoughts of independence on the part of separate cities, although the expedition against Erech and Naksu, which occurred in the patesiate of Lugal-ushumgal, supports the tradition of a revolt of all the lands in the latter part of Sargon's reign. ”
