For five hundred years the state of Qin - originally based on modern Shaanxi - had gradually been gobbling up its neighbours. In 221 BC its armies conquered the last pocket of resistance in the Middle Kingdom, east-coast Qi (Shandong), uniting the Chinese as a single centralized state for the first time, and implementing systems of currency and writing that were to last millennia. The rule of China's first emperor, Qin Shi Huang , was absolute: ancient literature and historical records were destroyed to wipe out any ideas that conflicted with his own, and peasants were forced off their land to work as labourers on his massive construction projects, which saw thousands of kilometres of roads, canals and an early version of the Great Wall , laid down across the new empire. Burning with ambition to rule the entire known world, Huang's armies gradually pushed beyond the Middle Kingdom, expanding Chinese rule, if not absolute control, west and southeast. But, though he introduced the basis of China's enduring legacy of bureaucratic government, Huang's 37-year reign was ultimately too self-centred - still apparent in the massive tomb (guarded by the famous Terracotta Army ) he had built for himself at his capital, Xi'an. When he died in 210 BC the provinces rose in revolt, and his heirs soon proved to lack the personal authority which had held his empire together. In 206 BC the rebel warlord Lui Bang took Xi'an, and founded the Han dynasty.