The document summarizes the unification of China under the Qin dynasty in 221 BCE and the subsequent Han dynasty that ruled from 206 BCE to 220 CE. It describes how the Qin used legalist policies like standardized laws and script to bring political stability after the warring states period. The Han dynasty consolidated centralized rule through Confucian education and expansion. However, economic prosperity led to social tensions that eventually contributed to the collapse of the Han dynasty in the 3rd century CE, dividing China again.