During the third millennium BC, intensive farming became widespread along theYellow and Yangzi River regions, where we also see the highest populationdensities and the most developed complex societies in the archaeological record.In contrast, hunting-gathering communities, sometimes incorporating low-levelfood production, appear to have continuously dominated the landscapes in manyother areas, such as the Northeast, Xinjiang, most areas in the Tibetan Plateau,and some parts of South China.

In the highly populated regions, some major social changes took place. Most ofthese societies were hierarchically organized, exchange of prestige goods was acommon practice among elite individuals, and intergroup warfare intensified.Political control, ritual power, and material wealth were closely related andconcentrated in small groups of elites. Regional centers were frequently builtwith walled enclosures, and some developed early forms of urbanism withpolitical, religious, and economic functions. In ancient Chinese texts thepolities in the Yellow River region have been referred to as “myriad(literally, ‘ten thousand’) states” prior to the firstdynasty, the Xia.