The Mesopotamia civilization started in 5300 BC. This period which was known as Ubaid period, was marked by the emergence of urban societies. Civilization included the sprouting of cities such as Uruk, Nippur, Nineveh, Assur and Babylon.
When they started to develop agriculture and their own form of writing which were like pictograms. They settled down because of the adbundunce of natural resources of the Nile Delta, and came to figure out how to plant and create agriculture that will replace hunter gatherer socioties because of the stable food that came from growing crops.