Before the Qin dynasty began in 221 B.C., the area that would become modern-day China was composed of seven major kingdoms. In 481 B.C., the leaders of the various kingdoms began jostling for greater authority, ushering in an era called the Warring States.
Qin Shi Huangdi (then known as Ying Zheng) positioned the Qin state to overtake the others by flexing its military muscle. He built up his army through conscription, or forced enrollment, and divided it into specialized units, which was a strategic innovation for that time [source: High Museum]. The military also utilized horses for the cavalry and perfected the crossbow, which allowed them to obliterate enemies. After achieving his goal of conquest, Emperor Qin set out to consolidate his power over these disparate lands.
To build his new empire, Qin needed money. But the six former states each traded with different forms of currency, such as squat, bladelike knife money in the northeast and the long, thin spade money in the central states. To remedy this, Emperor Qin introduced the banliang coin shaped like a tiny square donut. In ancient Chinese culture, the square symbolized the Earth and the circle represented the sky, which reveals Qin's high regard for the vastness of his empire. Emperor Qin also systemized weights and measurements along with the written language.
These standards unified the empire and also enabled the legalistic ruler to tax his citizens and enforce strict labor laws. With a mix of tyranny and brilliance, Qin organized the population into units of five to 10 families. Since the unit's well-being depended on everyone's obedience to laws, it ensured cooperation. Moreover, hundreds of thousands of Qin's subjects had no choice but to toil -- and sometimes die -- constructing the roads and canals the emperor desired. This citizen workforce also built the first Great Wall in China to protect Qin's empire from northern enemies.
Of course, not everyone readily succumbed to Emperor Qin's iron fist. He escaped three assassination attempts, which bred his intense fear of death. Above all, Qin yearned for immortality. He sent out convoys in search of a mythical island of everlasting youth and reportedly commissioned alchemists to concoct pills and potions to sustain his life [source: High Museum]. In case those tactics failed, Emperor Qin enlisted his subjects to build a dazzling burial complex with an impenetrable army to protect him in the afterlife.