The First Imperial Period
Background for Tu Zhiwei's mural, "Heads, Books, Pit"

China was unified for the first time in 221 B.C. when the western frontier state of Qin defeated the the last of its six rival states.

Once the king of Qin consolidated his power he took the title Shi Huangdi ( First Emperor).  Previously, this had been a title reserved for deities and the mythological sage-emperors. 

Qin established a centralized, nonhereditary bureaucratic system to run the far-flung empire, relying heavily on what was known as Legalism, a system of centralizing laws, coinage, administrative procedures, the writing system, and even acceptable modes of thought and scholarship.

This stamdardization was achieved by ruthless methods, however, and.it generated significant and widespread  opposition. To silence the criticism, the king banished or put to death many dissenting Confucian scholars and confiscated and burned their books ().

Qin also undertook significant public works projects, including a legendary effort to fortify and connect external fortress walls built in earlier times by the various Warring States. That  Great Wall () later was rebuilt and extended during the Western Han, Sui, Jin, and Ming periods. 

Revolts broke out as soon as the first Qin emperor died in 210 B.C. His dynasty was extinguished less than twenty years later. The imperial system initiated during the Qin dynasty, however, set a pattern that was developed over the next two millennia.