The last Shang ruler, a despot according to standard Chinese accounts, was overthrown by a chieftain of a frontier tribe called Zhou ,which had settled in the Wei Valley in modern Shaanxi Province. The Zhou dynasty had its capital at Hao , near the city of Xi'an ,or Chang'an , as it was known in its heyday in the imperial period. Sharing the language and culture of the Shang, the early Zhou rulers, through conquest and colonization, gradually sinicized, that is, extended Shang culture through much of China Proper north of the Chang Jiang ( to Yangtze River ). The Zhou dynasty lasted longer than any other, from 1027 to 221 B.C. It was philosophers of this period who first enunciated the doctrine of the "mandate of heaven" (tianming ), the notion that the ruler (the "son of heaven" ) governed by divine right but that his dethronement would prove that he had lost the mandate. At the same time, it was considered that the mandate was a reflection of people's will. The doctrine explained and justified the demise of the two earlier dynasties and at the same time supported the legitimacy of present and future rulers.
The term feudal has often been applied to the Zhou period because the Zhou's early decentralized rule invites comparison with medieval rule in Europe. At most, however, the early Zhou system was proto-feudal, being a more sophisticated version of earlier tribal organization, in which effective control depended more on familial ties than on feudal legal bonds. Whatever feudal elements there may have been decreased as time went on. The Zhou amalgam of city-states became progressively centralized and established increasingly impersonal political and economic institutions. These developments, which probably occurred in the latter Zhou period, were manifested in greater central control over local governments and a more routinized agricultural taxation.
In 771 B.C. the Zhou court was sacked, and its king was killed by invading barbarians who were allied with rebel lords. The capital was moved eastward to Luoyang in present-day Henan Province. Because of this shift, historians divide the Zhou era into Western Zhou (1027-771 B.C.) and Eastern Zhou (770-221 B.C.). With the royal line broken, the power of the Zhou court gradually diminished; the fragmentation of the kingdom accelerated. Eastern Zhou divides into two subperiods. The first, from 770 to 476 B.C., is called the Spring and Autumn Period , after a famous historical chronicle of the time; the second is known as the Warring States Period (475-221 B.C.).