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.
Literacy
Literacy emerged with the development of numeracy and computational devices as early as 8000 BCE. Script developed independently at least five times in human history Mesopotamia, Egypt, the Indus civilization, lowland Mesoamerica, and China.
The earliest forms of written communication originated in Serbia (Vinča culture), followed by Sumer, located in southern Mesopotamia about 3500-3000 BCE. During this era, literacy was "a largely functional matter, propelled by the need to manage the new quantities of information and the new type of governance created by trade and large scale production". Writing systems in Mesopotamia first emerged from a recording system in which people used impressed token markings to manage trade and agricultural production. The token system served as a precursor to early cuneiform writing once people began recording information on clay tablets. Proto-cuneiform texts exhibit not only numerical signs, but also ideograms depicting objects being counted.