Sargon I (ca. 2334-2279 BC) - The first known human to receive the epithet of "Great", Sargon was the first Mesopotamian ruler to unite the entire region. He did so at the expense of Sumer, the world's earliest civilization, and its king, Lugalzagesi. As he conquered Sumer, he established a new empire, Akkad, probably taking its name from Sargon's capital, Agade. The Akkadian Empire survived for another couple centuries and reached its peak under Sargon's grandson, Naram-Sin, but eventually collapsed from an invasion of a people known as the Gutians.