There were many great cities in the ancient Near East that influenced the course of history. Babylon and Jerusalem are two of the better known, but Nineveh, Damascus, Ur, Uruk, Memphis, Thebes, and Sidon were just a few of the great cities where science and literature were created, theologies proposed, and empires born. There are numerous reasons why these cities became prominent, many of which were related to the fortuitous circumstances of environment and politics, but for every one of the great cities, there were many more that flourished and then had their prestige overshadowed by the growth of their larger neighbors. These cities often played important roles in the historical processes of the region for a time, but due to numerous circumstances their influence proved to be ephemeral.One of the most interesting of these early ephemeral cities was Umma. Located in the southern region of Mesopotamia known as Sumer, Umma became a prominent Sumerian city in the early 3rd millennium BCE, and while Uruk was the most important Sumerian city during that era, Umma was close behind in influence and power and for a time seemed poised to become the most important place in Sumer. A powerful dynasty arose in Umma that expanded its influence across southern Mesopotamia, uniting the Sumerian cities under one government, but the central position that Umma enjoyed proved to be temporary because Semitic conquerors from the north forced Umma and the other cities to accept their rule.