A civilization is an advanced society characterized by a wide range of sophisticated cultural traits. A civilization is a complex, organized society that typically has religions and a written language, as well as a class system in which people are divided into various types of jobs. It also may have an economy, art forms like pottery and weaving, and other technological innovations. Its members often see themselves as morally superior to other people, including those outside their civilization.
Civilization first evolved from hunter-gatherer communities that settled into an agrarian lifestyle. As these communities became self-sufficient by producing surplus food, they needed to organize themselves into a hierarchical structure with special status for political and religious leaders. These leaders, known as kings or priests, gained status because they could make decisions that affected an entire society. They might be asked to perform large-scale irrigation projects or organize long-distance trade. They could then collect tribute from landowners, landless peasants, and specialized craftspeople in return for their services.
In general, early civilizations developed in river valleys. This was because rivers flooded regularly, spreading mineral-rich silt across the land, making it rich for agriculture. They were also near seas, which provided a constant supply of fish and other water creatures for food and trade. Early river valley civilizations included the Nile of Ancient Egypt, the Tigris and Euphrates of Mesopotamia, the Indus Valley region of India, and the Huang He (Yellow River) region of China.
Around 9,500 BCE, people in a handful of regions discovered agriculture, or the deliberate cultivation of edible plants. This was a huge step forward from the hunter-gatherer lifestyle of roaming around and hunting for wild animals to survive. Even primitive agriculture produces about fifty times more caloric energy than hunting and gathering does.
This discovery allowed people to live in permanent settlements, or cities, which were governed by elite rulers who demanded a quota of tribute from the citizens of the city-state. They used this food and wealth to pay for workers tasked with building things like temples, palaces, walls, and roads.
While the origins of civilization remain somewhat mysterious, it is likely that the people of a city-state needed to protect themselves from internal and external threats such as robbers and raiders. They also needed protection for their crops and access to services such as large-scale irrigation projects that were beyond the scope of neighborhood groups. In addition, they needed to maintain a stable supply of water for their crops and to feed themselves.
It is possible that early kings and priests, who controlled a portion of the food surplus from a city, took advantage of this fact to gain power. In many cases they probably did this through a balance of consensual and coercive power, but it is likely that this was the only way to sustain the high populations that cities created.