Rise of agriculture

A major change, described by prehistorian Vere Gordon Childe as the "Agricultural Revolution," occurred about the 10th millennium BCE with the adoption of agriculture. The Sumerians first began farming ca. 9500 BCE. By 7000 BCE, agriculture had spread to India; by 6000 BCE, to Egypt; by 5000 BCE, to China. About 2700 BCE, agriculture had come to Mesoamerica.
Although attention has tended to concentrate on the Middle East's Fertile Crescent, archaeology in the Americas, East Asia and Southeast Asia indicates that agricultural systems, using different crops and animals, may in some cases have developed there nearly as early. the development of organised irrigation, and the use of a specialised workforce, by the Sumerians, began about 5500 BCE. Stone was supplanted by bronze and iron in implements of agriculture and warfare. Agricultural settlements had until then been almost completely dependent on stone tools. In Eurasia, copper and bronze tools, decorations and weapons began to be commonplace about 3000 BCE. After bronze, the Eastern Mediterranean region, Middle East and China saw the introduction of iron tools and weapons.

The technological and social state of the world, circa 1000 BCE.
The Americas may not have had metal tools until the Chavín horizon (900 BCE). The Moche did have metal armor, knives and tableware. Even the metal-poor Inca had metal-tipped plows, at least after the conquest of Chimor. However, little archaeological research has so far been done in Peru, and nearly all the khipus (recording devices, in the form of knots, used by the Incas) were burned in the Spanish conquest of Peru. As late as 2004, entire cities were still being unearthed. Some digs suggest that steel may have been produced there before it was developed in Europe.
The cradles of early civilizations were river valleys, such as the Euphrates and Tigris valleys in Mesopotamia, the Nile valley in Egypt, the Indus valley in the Indian subcontinent, and the Yangtze and Yellow River valleys in China. Some nomadic peoples, such as the Indigenous Australians and the Bushmen of southern Africa, did not practice agriculture until relatively recent times.
Before 1800, many populations did not belong to states. Scientists disagree as to whether the term "tribe" should be applied to the kinds of societies that these people lived in. Many tribal societies, in Europe and elsewhere, transformed into states when they were threatened, or otherwise impinged on, by existing states. Examples are the Marcomanni, Poland and Lithuania. Some "tribes," such as the Kassites and the Manchus, conquered states and were absorbed by them.
Agriculture made possible complex societies — civilizations. States and markets emerged. Technologies enhanced people's ability to control nature and to develop transport and communication.