Human history (or the history of humanity), also known as the history of the world, is the carefully researched description of humanity's past. It is informed by archaeology, anthropology, genetics, linguistics, and other disciplines; and, for periods since the invention of writing, by recorded history and by secondary sources and studies.
Humanity's written history was preceded by its prehistory, beginning with the Palaeolithic Era ("Old Stone Age"), followed by the Neolithic Era ("New Stone Age"). The Neolithic saw the Agricultural Revolution begin, between 10,000 and 5000 BCE, in the Near East's Fertile Crescent. During this period, humans began the systematic husbandry of plants and animals.[2] As agriculture advanced, most humans transitioned from a nomadic to a settled lifestyle as farmers in permanent settlements. The relative security and increased productivity provided by farming allowed communities to expand into increasingly larger units, fostered by advances in transportation.
Whether in prehistoric or historic times, people always needed to be near reliable sources of potable water. Settlements developed as early as 4,000 BCE in Iran,[3][4][5][6][7] in Mesopotamia,[8] in the Indus River valley,[9] on the banks of Egypt's Nile River,[10][11] and along China's rivers.[12][13] 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.