The Zhou dynasty (1045-221 BC) was a dynasty that took over the dominant position in north China from the Shang dynasty and created the concept of the Mandate of Heaven to justify their rule. The Zhou era, particularly the vigorous early period (1045-771 BC) was remembered in Chinese tradition as a time of prosperity and benevolent rule. The dynasty descended into a series of civil wars in the Spring and Autumn Period and Warring States Period, and China was only reunified in 221 by the Qin dynasty.
The Zhou were acknowledged in Chinese traditions as among the western "barbarians" of the Wei River valley, and the two founders were King Wen of Zhou (a vassal ruler who initiated a rebellion of disaffected Shang subjects after being imprisoned) and his son Wu of Zhou (who mounted a successful attack on the Shang capital of Anyang and founded the Zhou dynasty). Zhou claimed that the last Shang ruler Zhou of Shang was depraved and tyrannical for neglecting to honor gods and ancestors and killing and abusing subjects. He claimed that the Mandate of Heaven meant that he was chosen by the gods to be the emperor, and during the Zhou dynasty, people prospered. Wu distributed territories to allies and his relatives, creating a system of feudalism. When Wu died, his young son Cheng of Zhou was too young, so his uncle, the Duke of Zhou, administrated the country selflessly. Confucius would celebrate him as the ideal administrator.
The Zhou built the new capital city of Xi'an and constructed buildings in the ancient concern of feng shui, in which buildings would have a harmonious relationship with nature. During the 11th to 8th centuries BC, the power of the Zhou monarch decreased due to the feudal division of territory and power. In 771 BC the Zhou capital was attacked by a coalition of enemies, forcing the Zhou to withdraw to Luoyang, ending the Western Zhou and beginning the Eastern Zhou period of 770-221 BC. The first era of the Eastern Zhou was the Spring and Autumn Period of 770 to 481 BC, where the states of the era fought each other through diplomatic initiatives, shifting alliances, coups and assassinations, and conventional assassinations. Unlike the battles of the Shang and Eastern Zhou, in which nobles on chariots fought each other to show their bravery, these battles were fought by large armies of conscripted farmers who fought bloody battles without any etiquette.
The Eastern Zhou's second era was the Warring States Period of 480-221 BC, in which the intensity of warfare between the rival states accelerated. By the start of the 3rd century BC, only seven major states remained, and the Qin dynasty in the western parts of the Central States (north and central China) under Qin Shi Huang would go on to reunite China.