Unification of China under Qin Shi Huang

Between 230 and 221 BCE, the state of Qin, under its king Ying Zheng, conquered the six other major rival states of the Warring States period, Han in 230, Zhao in 228, Wei in 225, Chu in 223, Yan in 222 and finally Qi in 221 BCE, ending centuries of division among competing Chinese kingdoms. Qin's strategy of allying with distant states while attacking nearer ones let it eliminate its rivals one at a time without facing a unified coalition, and immediately after Qi's fall in 221 BCE, Ying Zheng declared himself Qin Shi Huangdi, the First Emperor, replacing the old feudal order with a new centralized administration that divided the unified empire into thirty-six commanderies governed from the capital at Xianyang. Although the Qin dynasty itself collapsed only fifteen years later, its centralized bureaucratic model of imperial government, along with standardized weights, measures and script, became the enduring template that essentially every subsequent Chinese dynasty built upon. The unification of 221 BCE is conventionally treated as the founding moment of imperial China as a single political entity.