History of the world
Whether in prehistoric or historic times, people always needed to be near reliable sources of potable water. Settlements developed on river banks as early as 3000 BCE in Mesopotamia, on the banks of Egypt's Nile River, in the Indus River valley, and along China's rivers. As farming developed, grain agriculture became more sophisticated and prompted a division of labour to store food between growing seasons. Labour divisions led to the rise of a leisured upper class and the development of cities, which provided the foundation for civilization. The growing complexity of human societies necessitated systems of accounting and writing.
Iraqis
In ancient and medieval times Mesopotamia was the political and cultural centre of many great empires, such as the Akkadian Empire, Assyria, and Babylonia. The ancient Mesopotamian civilization of Sumer is the oldest known civilization in the world, and thus Iraq is widely known as the cradle of civilization. Iraq remained an important centre of civilization for millennia, up until the Abbasid Caliphate (of which Baghdad was the capital), which was the most advanced empire of the medieval world (see Islamic Golden Age).