Lü Clan disturbance

When Ying Bu rebelled in August or September 196 BCE, Emperor Gaozu of Han personally led the troops against Ying and received an arrow wound which allegedly led to his death the following year. His heir apparent Liu Ying took the throne and is posthumously known as Emperor Hui of Han (r.  195–188 BCE). Shortly afterward, Gaozu's widow Lü Zhi, now empress dowager, had two of her opponents murdered. Liu Ruyi, a potential claimant to the throne, was poisoned. His mother, Lady Qi, was brutally mutilated. When the teenage Emperor Hui discovered the cruel acts committed by his mother, Loewe says that he "did not dare disobey her." From that point, Emperor Hui only "indulged himself with wine and women" and no longer made key governing decisions, leaving them to his mother.

When Emperor Hui died in the autumn of 188 BCE, his son (whose parentage is disputed) ascended to the throne as Emperor Qianshao. There was no pretension that he was actually in charge: Emperor Hui's mother Empress Dowager Lü kept control of the imperial court. With Empress Dowager Lü acting as regent, she was the one who exercised the power of the emperor and decided who held that office, rendering the identity of the emperor rather meaningless. History describes her as "presiding over court and issuing edicts" (lin chao chengzhi 臨朝稱制).

In the winter of 188 BCE, Empress Lü decided to elevate her brothers as princes, despite Emperor Gaozu's ruling that only members of the imperial Liu clan could be ennobled as princes – a ruling that Empress Lü had a hand in creating. She was opposed by Chancellor of the Right Wang Ling (王陵) but was supported by Chancellor of the Left Chen Ping and the commander-in-chief of the armed forces, Marshal of State Zhou Bo. When Wang rebuked Chen and Zhou in private for contravening Gaozu's edict, they claimed that their compliance with Empress Dowager Lü's position was necessary to protect the empire and the Liu family.

Empress Dowager Lü then promoted Wang Ling to the position of Grand Tutor (太傅, taifu)— the emperor's teacher; Wang declined, claiming illness. Lü removed him from his position as Chancellor and sent him away from the capital to his fief of Anguo (安國, in modern Baoding, Hebei). She promoted Chen Ping to Chancellor of the Right, and promoted Superintendent of State Visits Fan Shiqi (審食其) to the office of Chancellor of the Left. Fan is described as a favoured servant of the empress, which may imply a romantic connection between the two.

Empress Dowager Lü then actioned her intent to ennoble her kin. In the summer of 187 BCE, her daughter Princess Yuan of Lu died. Afterwards, Empress Lü enfeoffed the princess's son, Zhang Yan (張偃), as Prince of Lu. Zhang Yan's father Zhang Ao had been Prince of Zhao during Gaozu's reign. He had been demoted as part of the policy against non-Liu princes, so Empress Dowager Lü might have felt that ennobling his son could be justifiable.

A month later, she required the emperor's officials to formally petition her to make her nephew Lü Tai (呂台) Prince of Lü – carving the principality out from the Principality of Qi. Continuing to consolidate her family's power, she arranged the marriage of Lü Lu's daughter to Liu Zhang, a grandson of Gaozu by descent from a different consort. She subsequently created Lu Zhang Marquess of Zhuxu (朱虛, present-day Linqu County, Shandong). The empress then enfeoffed a further two nephews to different ranks of marquess.

In 184 BCE, in an action unprecedented under the traditional patriarchy, Empress Lü ennobled her younger sister Lü Xu (呂嬃) as a marquise. In the spring of 181 BCE, Lü Tai's son Lü Chan (呂產), who had become Prince of Lü after his father's death, was given the larger Principality of Liang. He remained in the imperial court in Chang'an to serve as Grand Tutor and assist Empress Dowager Lü. Later that year, the empress made her nephew Lü Lu (呂祿) Prince of Zhao and another son of Lü Tai's, Lü Tong (呂通), Prince of Yan. Three more nephews were ennobled as marquesses.

In the summer of 180 BCE, Empress Dowager Lü Zhi died, having elevated ten relatives to noble ranks of prince or marquess, an assault against the power of the royal house. Immediately before her death, she had put Lü Lu and Lü Chan in charge of the imperial guards – Lü Lu in charge of the stronger northern division and Lü Chan in charge of the weaker southern division – and also the government. After her death, it was alleged that the Lü clan had a plan to overthrow the Han dynasty and assume imperial power themselves. Purportedly, this plan was leaked to Liu Zhang, the Marquess of Zhuxu and grandson of Emperor Gao through his oldest son Liu Fei (劉肥), who had married a daughter of Lü Lu and who had learned of the plan from his wife. Liu Zhang then planned a rebellion with his younger brother Liu Xingju, the Marquess of Dongmou, and their older brother Liu Xiang, the Prince of Qi. Under their plan, Liu Xiang would lead Qi forces against the capital, while Liu Zhang and Liu Xingju would persuade the imperial guards to rise up against the Lüs. If they were successful, they planned to have Liu Xiang declared emperor.

However, everything did not go to plan. In the autumn of 180 BCE, Liu Xiang did indeed start a military campaign with his own forces and also gained the support of the nearby Principality of Langye. Lü Chan sent Guan Ying (灌嬰), the Marquess of Yingyin, against the Qi forces, but Guan, unwilling to fight the Qi forces (because he actually distrusted the Lüs more than Qi), managed to negotiate a secret armistice with Liu Xiang, and both armies halted some distance apart from each other.

Allegedly, at this time, the Lüs were ready to take over the imperial dynasty but did not do so because they were concerned at the reactions of Zhou Bo, Liu Zhang, and the principalities of Qi and Chu. While the crisis was forming in Xi'an, so was a new conspiracy, involving:

• Liu Zhang
• Liu Xingju
• Zhou Bo (who, despite his title as commander of the armed forces, did not actually have control of the armed forces in the capital)
• Chen Ping (who, also despite his title as prime minister, did not have actual control of the government machinery)
• Guan Ying
• Cao Qu (曹窟), the Marquess of Pingyang and son of Cao Can (曹參), a former prime minister
• Li Ji (酈寄), the son of Li Shang, the Marquess of Quzhou and the best friend of Lü Lu
• Ji Tong (紀通), the Marquess of Xiangping
• Liu Jie (劉揭), the Minister of Vassal Affairs.

The conspirators first tried to get the Lüs to give up power voluntarily, by having Li Ji persuade Lü Lu that the best course of action for him and Lü Chan was to return to their principalities and turn over power to Zhou and Chen. Lü Lu agreed but was unable to reach a consensus with the Lü clan elders.

The conspirators then took drastic actions. Ji issued a forged imperial edict, ordering the northern division of the imperial guards to be turned over to Zhou. When the edict arrived at the northern division's camp, Li and Liu Jie persuaded Lü Lu that the edict was genuine and that he should obey it, and he did so. Zhou then, after requiring the guards to affirm their loyalty to the imperial Liu clan, took over the northern division.

The conspirators then took action against Lü Chan, who had not known of this turn in events. While Lü Chan was trying to enter the imperial palace (alleged by the conspirators later to be preparing for the takeover), Liu Zhang and Cao took control of the gates of the palace and had Lü Chan and his guards trapped in the courtyard. Zhou sent some soldiers to Liu Zhang, who fought with Lü Chan's guards and killed him in battle. Over the next few days, the Lü clan was slaughtered to the last person.

The conspirators argued that their actions were justified in order to protect Emperor Houshao against the Lü conspiracy, but once the Lüs were killed, they alleged that neither the emperor nor his brothers were in fact Emperor Hui's sons. Rather, they suggested that Empress Zhang Yan, Emperor Hui's wife, had stolen and adopted the boys at Empress Dowager Lü's instigation. They also admitted that they were concerned about reprisals when Emperor Houshao and his brothers grew up. They then agreed to depose Emperor Houshao and invite an imperial prince, not from Emperor Hui's line, to be the new emperor.

As to which prince to choose to be the new emperor, some of the conspirators suggested that Liu Xiang, being the eldest Di son (嫡長子) of Emperor Gao's oldest son (thus the eldest grandson of Emperor Gao), was the obvious choice. However, most of the important officials disagreed with this suggestion. They were concerned that Liu Xiang's uncle Si Jun (駟均) was a dominating figure and that, if Liu Xiang were to become emperor, they would have a repeat of the Lü clan situation. They believed that Emperor Gao's oldest surviving son, 23-year-old Prince Liu Heng of Dai, was the better choice, because he was known to be filial and tolerant, and because his mother Consort Bo 's family was known to be careful and kind. They then secretly sent messengers to Prince Heng, inviting him to be the new emperor.

In response to the invitation, Prince Heng's advisors were suspicious. Apparently, they felt that the massacre of the Lü clan was unjustified, and were concerned that the officials, in fact, had intended on making Prince Heng a puppet and were ready to take real power themselves. However, one of Prince Heng's advisors, Song Chang (宋昌), had a different opinion. He believed that the people were supportive of the Han dynasty and would not tolerate a takeover, and that given that there were many other principalities outside the capital, the officials, even if they had wanted to, would be unable to usurp imperial power. Still uncertain, Prince Heng sent his uncle Bo Zhao (薄昭) to Xi'an to meet with Zhou, who guaranteed that the officials were sincere in their invitation and had no ulterior motive. Bo believed them and urged Prince Heng to accept the offer.

Prince Heng then headed to Chang'an. During an evening ceremony at the Dai mission in the capital, the officials, led by Chen, offered the throne to Prince Heng, and he accepted, formally ascending the throne after declining four times, as Emperor Wen. That same night, Liu Xingju evicted Emperor Houshao from the imperial palace, and the officials welcomed Emperor Wen to the palace with great pomp.

Overall, the Lü Clan Disturbance had positive effects for the Han dynasty. It was affirmed that the power would rest with the emperor. Further, and more importantly, Emperor Wen became an effective, thrifty, hard-working and benevolent ruler, and the reigns of Emperor Wen and his son Emperor Jing were generally regarded as one of the golden ages of Chinese history. What happened to the Lü clan has often been used throughout Chinese history as a warning to the families of empresses not to assume too much power, and to emperors not to allow them to do so.

• Sima Qian; Sima Tan (1959) [90s BCE]. "9: 呂太后本紀". Records of the Grand Historian 史記. Zhonghua Shuju.
• Ban Gu; Ban Zhao; Ban Biao (1962) [111]. "3: 高后紀". Book of Han 漢書. Zhonghua Shuju.