Zhou Dynasty which began between 1045?-256 bc, also known as Chou was a Chinese dynasty that paved the way for the first unification of China in 221 bc. Although the Zhou dynasty was founded in about 1027 BC, the Zhou conquest of the Shang dynasty in about 1045 BC established the Zhou as the supreme political power in China. Most historians date the beginning of the Zhou dynasty to this event, and Zhou historical records show that the Zhou themselves considered this victory to be the beginning of their dynastic reign.
The Zhou dynasty is subdivided into two periods: the Western and Eastern Zhou. The Western Zhou controlled China’s Central Plain area, consisting mainly of the middle and lower reaches of the Huang He (Yellow River) drainage. The authority of the Western Zhou court ended in 771 bc, but the Eastern Zhou court nominally reigned until 256 bc. During this period, the area of China expanded to include the drainage of the Yangtze River in the south as well as the farmland along the future site of the Great Wall in the north.
During the Zhou dynasty, China evolved from a feudal state with power divided among vassals to one with a strong centralized government. Paralleling this change visible during the Zhou dynasty, a more homogeneous Chinese civilization developed as contact between regions increased and Confucianism spread throughout China.