Mesopotamians are noted for their dense populations, urbanization processes, and cultural innovation. These elements are tied to the growth of commerce and broader cultural interaction. That is, as empires these civilizations can be thought of as collections of peoples, goods, and ideas whose existence and dynamism were built on movement and exchange. This can be seen in the movement and exchange of people, the movement and exchange of goods, and the movement and exchange of ideas.
Two cultural groups form the principle elements in the population of Mesopotamia before the beginning of history and in the millennium thereafter (the 3rd millennium BCE). These are the Sumerians and the Akkadians. The people who settled down and began to develop a civilization, in the land between two rivers, are known as the Sumerians. They lived peacefully together and created in mutual fertilization, by symbiosis and osmosis, the conditions for a common high civilization.
Mesopotamian sources in all periods seem to be free of strong racial ideologies or ethnic stereotypes. Enemies, both groups and individuals, may be cursed and reviled heavily, but this applies more strongly to the ruler of a nearby city than to one of a remote territory.
Akkadians or Semi-nomads in the Near East. Even at the time that a large part of the population in Mesopotamia had a sedentary (non-migratory) life in settlements; large groups of people at the same time were migrating. Mesopotamia's neighbors in the 3rd millennium in the east were the Elamites, in the west was the city of Ebla, the other neighbors were Gutians, Amorites, Kassites, Hittites, Sea people, Arameans.
The city of Babylon makes its first appearance in our sources after the fall of the Empire of the Third Dynasty of Ur, which had ruled the city states of the alluvial plain between the rivers Euphrates and Tigris for more than a century (2112-2004?). The Hurrians enter the orbit of ancient Middle Eastern civilization toward the end of the 3rd millennium BC. They arrived in Mesopotamia from the north or the east, but it is not known how long they had lived in the peripheral regions.
The Kassites had settled by 1800 BC in what is now western Iran in the region of Hamadan-Kermanshah. The first to feel their forward thrust was Samsuiluna, who had to repel groups of Kassite invaders. Increasing numbers of Kassites gradually reached Babylonia and other parts of Mesopotamia. There they founded principalities, of which little is known.