The Han dynasty’s 406 year reign had a brief intermission. Between the Western Han dynasty and the Eastern Han dynasty, there was a usurper of power.
Wang Zhenjun was an empress, then empress dowager, and finally, a grand empress dowager during the time of Western Han’s Emperor Ai. Her male relatives also held the title of regent. Upon Ai’s death, Zhenjun’s nephew, Wang Mang, was appointed regent as Marshall of State under Emperor Ping.
Various successors
When Ping died in 6 BCE, Liu Ying was chosen as the heir and Wang Mang was appointed to serve as acting emperor in his place. Wang pledged to let Liu Ying take his rightful place on the throne when he came of age. But when the time came, and against the protest and revolts of the nobility, Wang Mang claimed that the Divine Mandate of Heaven called for the end of the Han Dynasty and the beginning of his own, the Xin Dynasty.
While he was merely advising the young emperors, Wang Mang embarked on a program of building and learning, trying to foster as much goodwill as possible for himself. He presented himself as a champion for Confucian virtues and made it seem as though he would pattern the new empire in accordance with them. When Wang Mang seated himself on the throne, the old bureaucracy and nobility were still loyal to the Han dynasty, but they didn’t openly oppose the establishment of the Xin regime.
Xiongnu rivals
Han was also in a strange stalemate with the Xiongnu confederation, a tribal group of nomadic people. Relations with the Xiongnu confederation quickly deteriorated, and they intended to invade China. Wang prevented this by mobilizing 300,000 soldiers. The continuing dispute between the confederations led to Wang creating a rival Xiongnu government in 19 BCE, while maintaining the great army at the border. This slowly drained the Xin dynasty’s resource, weakening its grip on the empire.
Several radical social and political reforms were initiated aiming to strengthen the central government, restoring the failing economy, weakening the powerful noble families, and improving the livelihood of the empire’s peasants. And while there was some initial success in strengthening the legitimacy of the current regime, the reforms weakened the former imperial clan. Wang’s reforms were resented by the old bureaucracy and often were ignored. These reforms did find some acclaim among the empire’s peasants.
While it is sometimes said that he abolished the slave trade, this is false. He didn’t free the slaves. Instead, he proclaimed slaves to be private property that can’t be resold. And this was eventually withdrawn because of the resistance of slave owners.
Rapid decline
Wang’s regime was quickly destabilized by several natural disasters, like floods, plagues of locusts, and famine. The Xin policies did little to solve the crises, and he lost all the support of the peasantry. Some peasants on the eastern parts turned to banditry and grew in numbers and strength.
They started to reorganize into rebel armies that allied with discontent nobles and descendants of the former imperial clan resulting in a large-scale civil war by 19 BCE. Wang Mang was forced to shift troops from other areas to deal with the Red Eyebrows, whereupon an area of the western region was overrun by the Xiongnu. Havoc ensued across the country and engulfed China.
Despite the efforts of Xin Empire loyalists, they were defeated by Han restorationists in the Battle of Kunyang. The Xin Dynasty was short-lived, only lasting from 9-23 BCE. In 25 AD, Liu Xu was crowned as Emperor Guangwu of Han.
Historians who lived during the Han dynasty ridiculed Wang Mang’s movement to return to the order of the Zhou dynasty as neither practical nor successful, but the Xin dynasty’s attempted reforms served as an inspiration for later emperors. According to Li Feng, Wang Mang would have been “the greatest reformer in Chinese history” if his regime had survived.
In case you missed it, you can also read about the Western Han dynasty, Qin dynasty, Zhou dynasty, Shang dynasty, and the Xia dynasty, as well as what came before the first Chinese dynasty here.