Eannatum, the Sumerian king of Lagash, established one of the first verifiable empires in history in 2500 BC. The neighboring Elam, in modern Iran, was also part of the early urbanization during the Chalcolithic period. Elamite states were among the leading political forces of the Ancient Near East. The emergence of Elamite written records from around 3000 BC also parallels Sumerian history, where slightly earlier records have been found. During the 3rd millennium BC, there developed a very intimate cultural symbiosis between the Sumerians and the Akkadians. Akkadian gradually replaced Sumerian as a spoken language somewhere between the 3rd and the 2nd millennia BC. The Semitic-speaking Akkadian empire emerged around 2350 BC under Sargon the Great. The Akkadian Empire reached its political peak between the 24th and 22nd centuries BC. Under Sargon and his successors, the Akkadian language was briefly imposed on neighboring conquered states such as Elam and Gutium. After the fall of the Akkadian Empire and the overthrow of the Gutians, there was a brief reassertion of Sumerian dominance in Mesopotamia under the Third Dynasty of Ur. After the final collapse of Sumerian hegemony in Mesopotamia around 2004 BC, the Semitic Akkadian people of Mesopotamia eventually coalesced into two major Akkadian-speaking nations: Assyria in the north, and, a few centuries later, Babylonia in the south.