Overview
King Zheng of Qin completed the conquest of the rival states in 221 BC and took the new title Shi Huangdi, “First Emperor”. His rule was harsh and Legalist.
Key developments
The Qin replaced feudal lords with centrally appointed commanderies and counties. It standardized the writing script, weights and measures, currency, and cart-axle widths, built roads, and connected existing northern walls into an early Great Wall.
End and transition
After the First Emperor died in 210 BC, revolts broke out, beginning with Chen Sheng and Wu Guang in 209 BC, and the dynasty fell in 206 BC.