Who were the semi-nomadic people that migrated and settled in the Tigris-Euphrates valley during the 4th millennium B.C.E.?

The Akkadians were the semi-nomadic people who migrated and settled in the Tigris-Euphrates valley during the 4th millennium B.C.E. This period marked significant developments in Mesopotamia, where the Akkadians began to establish their presence and influence. They played a vital role in the formation of one of the world's first great empires, as they transitioned from a nomadic lifestyle to more settled urban centers, particularly under the leadership of figures such as Sargon of Akkad. The Akkadian Empire ultimately unified various city-states in the region, contributing to political and cultural advancements.

The other groups mentioned, such as the Sumerians, Amorites, and Babylonians, were also significant players in the history of Mesopotamia but emerged and developed later or in different contexts. The Sumerians, for instance, were already established in the region by the time of the Akkadian rise, and the Babylonians arose afterward from the Amorite tribes. This context allows for a better understanding of how the Akkadians fit into the broader narrative of ancient Mesopotamia.