The oldest evidence for a civilization, defined by urban development, social stratification, writing systems and agriculture, comes from the Mesopotamian region between the Tigris and Euphrates rivers of the Middle East. The region held the city of Uruk, which was one of the earliest cities.
The Fertile Crescent, as Mesopotamia is referred to by modern scholars, is the location of the first developed civilization anywhere in the world. As early as 10,000 B.C., agriculture was developed in the region.
Subsequent independent civilizations arose after this time in China, Egypt and the Americas. Generally, the development of a sedentary agricultural population was the precursor of organized civilization. As the people of the areas transitioned from egalitarian roaming hunter-gatherer activities to specialized farming ones, a class system developed to manage the specializations.