Sumer
Sumer () is the earliest known civilization in the historical region of southern Mesopotamia, modern-day southern Iraq, during the Chalcolithic and Early Bronze ages, and one of the first civilizations in the world along with Ancient Egypt and the Indus Valley. Living along the valleys of the Tigris and Euphrates, Sumerian farmers were able to grow an abundance of grain and other crops, the surplus of which enabled them to settle in one place. Prehistoric proto-writing dates back before 3000 BC. The earliest texts, from c. 3300 BC, come from the cities of Uruk and Jemdet Nasr; early cuneiform script emerged around 3000 BC.
Ancient history
Mesopotamia is the site of some of the earliest known civilizations in the world. Early settlement of the alluvial plain lasted from the Ubaid period (late 6th millennium BC) through the Uruk period (4th millennium BC) and the Dynastic periods (3rd millennium BC) until the rise of Babylon in the early 2nd millennium BC. The surplus of storable foodstuffs created by this economy allowed the population to settle in one place instead of migrating after crops and herds. It also allowed for a much greater population density, and in turn required an extensive labor force and division of labor. This organization led to the necessity of record keeping and the development of writing (c. 3500 BC).