In 33 BC, Emperor Yuan of Han died, and his son Liu Ao ascended the throne as Emperor Cheng of Han. Empress Dowager Wang Zhengjun, Emperor Yuan's consort, became the grand empress dowager, and members of the Wang family one after another assumed high-ranking official positions, inevitably becoming somewhat arrogant and losing their sense of propriety. Their lives gradually grew extravagant, indulging day and night in wine and women, and they flaunted the Wang family's illustrious status. Others detested the Wangs but dared not show it. The empress dowager had a nephew named Wang Mang, who, while the Wang family was making a grand show of power at court, quietly stayed at home caring for his aging mother. Wang Mang had an elder brother who unfortunately died young, leaving behind a widow and orphan, whom Wang Mang also looked after. Besides fulfilling his filial duties, Wang Mang studied the Book of Rites under a renowned teacher, treating everyone with courtesy and never flaunting his Wang family connections. In the eyes of others, Wang Mang was practically a model of virtue.
Grand Sima Wang Feng, who was Wang Mang's uncle, held Wang Mang in high regard and, on his deathbed, specifically urged Empress Dowager Wang to take good care of Wang Mang. The Empress Dowager then appointed Wang Mang as Gentleman of the Yellow Gate, and later promoted him to Colonel of the Shooting Sound, which occurred in 22 BC. Not only Wang Feng, but other court officials also admired Wang Mang and frequently praised him before Emperor Cheng of Han. His uncle Wang Shang even requested that the emperor grant half of his own fiefdom to Wang Mang. Emperor Cheng, constantly hearing others' praises of Wang Mang, believed that Wang Mang truly had the ability to win widespread admiration, so in 16 BC, he elevated him to Marquis of Xindu and additionally appointed him as Colonel of Cavalry, Grand Master of Splendid Happiness, and Attendant-in-Ordinary. After becoming a high-ranking official, Wang Mang remained as humble as before, even more so, treating both subordinates and commoners with courtesy. On one occasion, he sold his own carriage and donated the proceeds to the poor. Whenever the people mentioned Wang Mang, they were full of praise and reverence. Although many members of the Wang family held high offices, they did not enjoy as high a status in the hearts of the people as Wang Mang did.
Another Grand Marshal, Wang Gen, when retiring to his hometown, recommended Wang Mang to Emperor Cheng of Han as his successor, and the emperor agreed. Thus, Wang Mang became the fourth member of the Wang clan to hold the position of Grand Marshal, at the young age of 38. The wealth bestowed by the emperor was all used by Wang Mang to aid the poor and entertain scholars and literati, while he himself maintained a frugal lifestyle, with his family dressed in plain, muted colors. Once, when officials visited Wang Mang's home, they mistook his wife for a servant, because her attire was nothing like the bright, luxurious clothing typical of a wealthy household.
In 7 BCE, Emperor Cheng of Han died, and Emperor Ai ascended the throne. Only six years later, Emperor Ai also died, and Empress Dowager Wang installed Liu Kan, the eight-year-old grandson of Emperor Yuan, as emperor, known as Emperor Ping of Han. Wang Mang continued to serve as Grand Marshal, and with the emperor still young, power gradually fell into the hands of Empress Dowager Wang and Wang Mang. Initially, no one opposed this, and many were relieved that the young ruler had Wang Mang's support. However, under the influence of power and ambition, Wang Mang's mindset changed, and his political ambitions slowly emerged. He used Empress Dowager Wang to drive away his uncle Wang Li, then appointed Kong Guang's son, a veteran official of three reigns, as Attendant and Chariot and Horse Commandant, forcing Kong Guang to work for him. Kong Guang had no choice but to speak highly of Wang Mang in court before the emperor and officials. Wang Mang then targeted those who opposed him, causing several ministers to be dismissed one after another, including Chief Palace Attendant Shi Li, Nan Commandery Governor Wujiang Long, Henei Governor Zhao Chang, and Mount Tai Governor Ding Xuan. He also stripped the noble titles of Gao Chang Marquis Dong Wu and Guan Nei Marquis Zhang You. Wang Mang placed his own confidants in the court, and at his command, they immediately carried out his orders. Thus, every so often, the ministers would petition the emperor and empress dowager to grant Wang Mang higher titles and honors. Wang Mang always sternly refused, even tearfully claiming he was unworthy of such rewards. After several such episodes, the empress dowager began urging him to accept the ministers' goodwill. Wang Mang would put up a pretense of refusal before reluctantly accepting the titles. In this way, Wang Mang was granted the title "Duke Who Pacifies Han" and, along with Kong Guang, Wang Shun, and Zhen Feng, became one of the "Four Pillars." From then on, Wang Mang could be said to be second only to the emperor, above all others.
In 3 AD, Wang Mang married his daughter to Emperor Ping of Han. In 4 AD, Emperor Ping granted Wang Mang the title of Zaiheng, placing him above all the princes. To further win popular support, Wang Mang summoned scholars and literati from across the country to Chang'an, promoting Confucianism and earning widespread praise from Confucian scholars. He also ordered the construction of many marketplaces and granaries, which won him acclaim from the common people. In 5 AD, Emperor Ping died, and Wang Mang, wanting to seize the throne but fearing opposition from the realm, used his power to install the two-year-old Liu Ying as the crown prince, while he himself was appointed by the Empress Dowager Wang as the "acting emperor."
Temporarily managing court affairs. Wang Mang's ambition grew increasingly, and gradually, the Liu family sensed Wang Mang's unusual behavior and decided to raise troops to rebel. In 6 AD, Marquis Liu Chong of Anzhong led over a hundred men in an attempt to capture Wancheng but failed; the following year, Marquis Liu Xin of Yanxiang joined forces with Zhai Yi, the Governor of Dong Commandery, to raise an army and proclaimed himself emperor. Overnight, rebellions of various sizes erupted, and Wang Mang panicked, unsure of what to do. On one hand, he swore to the ancestors of the Liu family that he would never betray the state, and on the other, he ordered his troops to suppress the uprisings. By 8 AD, the momentum of the rebellions was quelled, and Wang Mang began preparations to ascend the throne. He secretly instructed others to spread rumors in public that he was the true Son of Heaven, then forced the Empress Dowager Wang to hand over the imperial seal, declaring to the world that Crown Prince Liu Ying had abdicated the throne to him. Thus, in 9 AD, Wang Mang ascended the throne as the true emperor, establishing the dynasty name "Xin."
During the late Western Han Dynasty, society was highly unstable, with chaotic national policies disrupting the daily lives of the common people. Many were forced to leave their homes, turning some areas into uninhabited wastelands. To ease social tensions, Wang Mang, after ascending the throne, implemented a series of reforms modeled after the Western Zhou system. He abolished the unified Wuzhu coinage of the Han Dynasty and impracticality introduced various new currencies; nationalized all land, distributing it according to household size and requiring landlords and wealthy merchants to surrender excess land; banned the sale of slaves; prohibited usury and controlled prices; placed all salt, iron, coinage, and liquor production under state management; and initiated a wave of renaming places, arbitrarily redrawing administrative and official jurisdictions.
As soon as the policy was announced nationwide, it sparked widespread anger and opposition, with the most intense resistance coming from wealthy landowners and local strongmen. Wang Mang's reforms infringed on the interests of the rich to varying degrees, fostering hostility toward his rule. Many wealthy individuals refused to hand over their land to the state, and since the state naturally lacked enough fields to distribute to the common people, the populace was filled with grievances. The reckless minting of coins threw the national economy into chaos, with prices impossible to stabilize, economic growth stagnating or even regressing. Local officials, unable to adapt quickly to the changes in place names, frequently made errors in handling official affairs, which inevitably bred resentment toward Wang Mang as well.
Additionally, Wang Mang lowered the status of ethnic minorities, forcing them to bow and submit to him. The leaders of various tribes were extremely angered, which subsequently triggered wars between the minorities and the Central Plains. Wang Mang dispatched a massive army of one hundred thousand troops to the border to confront them. Maintaining the army incurred enormous expenses, and the national treasury was gradually depleted. At this time, plagues, droughts, locust plagues, and the breach of the Yellow River broke out, catching the rulers off guard and plunging the realm into turmoil. Wang Mang's reforms not only failed to promote development but instead threw the country into chaos.