Sedentary agricultural communities were established in different parts of China form the 7th millennium BCE and they underwent a slow process of demographic expansion, economic diversification and social stratification. This relatively gradual process of socio-political evolution intensified and become more punctuated during the third and second millennia BCE. In this paper I will address two periods of upheaval and transformation: 1. the end of the third millennium BCE, when many of the large Neolithic sites (or cities) ceased to exist while a few – most notably Erlitou, the suppose center of the Xia dynasty – emerged as regional centers. 2. The period from c. 1150 to 1040 BCE, when the Shang state which dominated north and central China underwent a period of decline until it collapsed and was replaced by a coalition that formed the new Zhou state. At the same time, societies on the northern frontiers of China also underwent dramatic processes of change.

The paper will analyze those dramatic processes of political collapse and social transformation and will entertain possible causes, including climatic and environmental change.