Biography
Imperial Prince and the Succession
Li Heng's mother, Lady Guo, came from a prominent family. She was a granddaughter of Guo Ziyi and the daughter of imperial son-in-law Guo Ai and Princess Shengping. After Emperor Xianzong took the throne, Lady Guo long lacked the formal title of empress, but she held a very high position within the palace and among the emperor's maternal relatives. Following the death of Crown Prince Li Ning, differing views arose over the succession, and Li Heng ultimately prevailed. His selection reflected not only his age and order among the imperial sons, but also the support of the Guo family, palace eunuchs, and officials.
Accession and Political Style
Emperor Xianzong died suddenly in 820. Historical sources offer different clues about the cause, including assassination by eunuchs and illness caused by alchemical elixirs. After Li Heng rapidly succeeded to the throne, he did not fundamentally alter the situation in which eunuchs controlled the Shence Army and palace information. In contrast with the prolonged warfare of Xianzong's later reign, Muzong and his chief ministers hoped to reduce military expenditure and restore routine administration, but this policy shift did not adequately address the social conditions of the military governorships.
Li Heng was fond of outings and banquets, music, polo, and palace construction. Many ministers urged him to hunt less and devote himself more closely to government. He often accepted their advice verbally but made few lasting changes. It would be insufficient to attribute every political failure solely to his lifestyle, yet the emperor's inability to provide sustained direction did make changes of chief ministers, eunuch influence, and local crises harder to coordinate.
Renewed Rebellion of the Hebei Military Governorships
By the end of the Yuanhe era, the court had temporarily forced the Hebei military governorships to submit. Muzong's government believed the conflict had been settled and ordered the circuits to reduce a certain proportion of their troops. The discharged soldiers had no stable livelihood, and discontent within the military communities quickly grew. The Lulong army raised Zhu Kerong to power, while the Chengde army supported Wang Tingcou and killed Tian Hongzheng, whom the court had appointed. Tang forces campaigned by several routes without unified command, and both supply and leadership were problematic. In the end, the court could only grant the rebel leaders formal titles as military governors. The restoration of de facto separatism in Hebei showed that the military achievements of the Yuanhe era had not been converted into durable institutional control.
The Changqing-Era Treaty and the Frontier
During Muzong's reign, Tang and Tibet made peace, holding negotiations in Chang'an and erecting stelae in Lhasa and elsewhere. The text confirmed the frontier and peaceful intercourse; later generations referred to this as the treaty concluded in the Changqing era. The agreement did not permanently end frontier conflict, but it reflected a shared desire by Tang and Tibet to reduce the costs of prolonged warfare and brought a period of relative stability to their borderlands.
Illness and Death
In 822, Li Heng was frightened and fell, or otherwise became ill, during a palace polo game and remained in poor health for a long period. The choice of crown prince and the operation of the court consequently drew greater attention. Li Heng later consumed elixirs supplied by practitioners, and his health continued to deteriorate. He died early in 824 at only thirty years of age. His son Li Zhan succeeded him as Emperor Jingzong of Tang, while the problems of palace recreation and eunuch politics remained unresolved.
Li Heng, the emperor Muzong of the Tang, was originally named Li You and was the third son of Emperor Xianzong. Born in the seventh month of 795 in a side hall of the Daming palace, he was first made prince of Jian'an and in 806 prince of Sui, and in 810 was given command of the Zhangyi army and other posts. His mother was the consort Guo, whom Xianzong had married in 793 when he was prince of Guangling; she was a granddaughter of the "honored father" Guo Ziyi, who had restored the Tang house, and her family was immensely powerful at court — the fundamental reason why Li You could succeed to the throne.
Xianzong long hesitated over the succession. Before his accession he already had an eldest son Li Ning and a second son Li Yun, whose mothers, a palace woman of the Ji family and a woman whose name is not recorded, were of no consequence beside the Guo connection. The matter dragged on until the third month of 809, when the emperor's mind turned gradually to the eldest son: Li Ning was then seventeen, fond of books and correct in his conduct, and pleased his father, so that on his ministers' prompting Xianzong declared him heir. The investiture was troublesome: meant for the spring, it was postponed again and again by heavy rain and did not take place until the tenth month, and how much pressure came from the Guo family in the interval is not known. In the twelfth month of 811, after two years as heir, Li Ning died of illness at nineteen. Xianzong mourned him bitterly, closed the court for thirteen days, devised special mourning rites and gave him the posthumous title of the Huizhao heir. The succession was again open: almost everyone inside and outside the court proposed the third son Li You, born of the consort Guo, and only a few argued for the second son by order of birth. Xianzong was inclined to the second son, but Li Yun's mother was of low station and could not command support, while the Guo party was far too strong, and the cry for the third son prevailed. The emperor had no choice but to have Cui Qun draft, on Li Yun's behalf, a memorial declining; in the seventh month of 812 he decreed Li You heir, changing his name to Li Heng, and the investiture was held in the tenth month.
Xianzong was not, however, satisfied with this heir, and the eunuch Tutu Chengcui, reading the emperor's mind, never gave up working for Li Yun. In the tenth month of 813 the officials who had supported the heir memorialized again, asking that the consort Guo be made empress; Xianzong refused on various pretexts — since Wu Zetian, few empresses had been made while alive, and the Guo connection was in any case too strong. The consort Guo thereafter gathered partisans both at court and outside, including powerful eunuchs, contending in secret with Tutu Chengcui. At the end of 814, with Xianzong's health failing from the elixirs he took, Tutu Chengcui pressed harder to replace the heir. Li Heng was badly alarmed and asked counsel of his uncle Guo Zhao, who told him to attend only to filial piety and duty and think of nothing else — the heir's party, plainly, had made its preparations and was waiting. On the twenty-seventh day of the first month of 820 Xianzong died suddenly in the palace; contemporaries said he had been murdered by the eunuch Chen Hongzhi, while others held that he died of the golden elixir, and the eunuchs Liang Shouqian and Wang Shoucheng at once set up the heir, who took the throne as Muzong, while Tutu Chengcui and the second son Li Yun were killed in the coup. Muzong made his mother the consort Guo empress dowager and changed the place names that offended his personal name.
The era names of Muzong's reign were first Yongxin and then Changqing; his chancellors in turn included Xiao Mian, Duan Wenchang, Cui Zhi, Du Yuanying and Li Fengji, most of them intent on keeping their places and pleasing their master. He did issue orders releasing palace women and reducing the court musicians, but such measures went side by side with his building on a great scale and his favor to the alchemists, and cannot be called clean government.