Chinese language, measurements, length of cart axles, and currency. The Qin Dynasty lasted only fifteen years, falling soon after Qin Shi Huang's death, as its harsh legalist and authoritarian policies led to widespread rebellion.
The subsequent Han Dynasty ruled China between 206 BC and 220 AD, and created a lasting Han cultural identity among its populace that extends to the present day. The Han Dynasty expanded the empire's territory considerably with military campaigns reaching Korea, Vietnam, Mongolia and Central Asia, and also helped establish the Silk Road in Central Asia. China was for a large part of the last two millennia the world's largest economy. However, in the later part of the Qing Dynasty, China's economic development began to slow and Europe's rapid development in the Industrial Revolution enabled it to surpass China.
After the collapse of Han, another period of disunion followed, including the highly chivalric period of the Three Kingdoms. Independent Chinese states of this period such as Wu opened diplomatic relations with Japan, introducing the Chinese writing system there. In 580 AD, China was reunited under the Sui. However, the Sui Dynasty declined following its defeat in the Goguryeo–Sui War (598–614).
Under the succeeding Tang and Song dynasties, Chinese technology and culture entered a golden age. The Tang Empire was at its height of power until the middle of the 8th century, when the An Shi Rebellion destroyed the prosperity of the empire. The Song Dynasty was the first government in world history to issue paper money and the first Chinese polity to establish a permanent standing navy. Between the 10th and 11th centuries, the population of China doubled in size. This growth came about through expanded rice cultivation in central and southern China, and the production of abundant food surpluses.
Within its borders, the Northern Song Dynasty had a population of some 100 million people. The Song Dynasty was