Much of what came to constitute China Proper was unified for the first time in 221 BC. In that year the western frontier state of Qin, the most aggressive of the Warring States, subjugated the last of its rival states (Qin is pronounced Ch'in, from which the English China probably derived).
Once the king of Qin consolidated his power, he took the title Shi Huangdi or First Emperor, a formulation previously reserved for deities and the mythological sage-emperors and imposed Qin's centralized, nonhereditary bureaucratic system on his new empire. In subjugating the six other major states of Eastern Zhou, the Qin kings had relied heavily on Legalist scholar-advisers. Centralization, achieved by ruthless methods, was focused on standardizing legal codes and bureaucratic procedures, the forms of writing and coinage and the pattern of thought and scholarship.
To silence criticism of imperial rule, the kings banished, or put to death, many dissenting Confucian scholars confiscating and burning their books. Qin aggrandizement was aided by frequent military expeditions pushing forward the frontiers in the north and south. To fend off barbarian intrusion, the fortification walls built by various warring states were connected to make a 5,000-kilometer long great wall .
What is commonly referred to as the Great Wall is actually four great walls rebuilt or extended during the Western Han, Sui, Jin, and Ming periods rather than a single, continuous wall. At its extremities, the Great Wall reaches from northeastern Heilongjiang Province to northwestern Gansu.
To achieve eternal peace, the emperor started the construction of his tomb, presently known as Terra Cotta Soldiers Tomb, before his death.
A number of public works projects were also undertaken to consolidate and strengthen imperial rule. These activities required enormous levies of manpower and resources, not to mention repressive measures. Revolts broke out as soon as the first Qin emperor died in 210 BC. His dynasty was extinguished less than twenty years after its triumph.
The imperial system initiated during the Qin dynasty, however, set a pattern that was developed over the next two millennia.
The period from 221 B.C. to 207 B.C. is known as the Qin Dynasty. This dynasty was vigorous but short-lived. It was the first emperor of the dynasty, Qin Shihuangdi who united the Warring States into an empire.
The outstanding achievement of the Qin was the centralization of Chinese government in a nonfeudal, nonhereditary, bureaucratic administration which established a pattern of freehold farmers throughout China. Weights and measures, coinage,and script were standardized throughout the country. Efforts to control society led to strict censorship and the persecution of philosophers and scholars. The power of the throne was visible in the building of grand palaces and large scale construction projects such as roads, waterways, and the beginning of the Great Wall. Such vast projects were made possible largely through the forced labor of hundreds of thousands of subjects who had been convicted and sentenced for not adhering to the strict rules set forth by the ruling powers. Great armies were built to enforce the policies of centralization.