Emperor Suzong of Tang (yihai day, 711 – 16 May 762; r. 756 – 762), personal name Li Heng, né Li Sisheng (), known as Li Jun () from 725 to 736, known as Li Yu () from 736 to 738, known briefly as Li Shao () in 738, was an emperor of the Chinese Tang dynasty and the son of Emperor Xuanzong.
Suzong ascended the throne after his father fled to Sichuan during the An Lushan Rebellion in 756; Li Heng himself had fled in the opposite direction, to Lingwu, where he was declared emperor by the army. Much of Emperor Suzong's reign was spent in quelling the aforementioned rebellion, which was ultimately put down in 763 during the reign of his son Emperor Daizong.
During Emperor Suzong's reign, the tradition of eunuchs becoming top-ranked officials began, with Li Fuguo becoming the commander of the imperial guards and possessing nearly absolute power near Emperor Suzong's reign. Later, Empreror Suzong favored Empress Zhang and allowed her to interfere in court politics.
Li Fuguo allied and befriended Emperor Suzong's wife, Empress Zhang, at the beginning of Emperor Suzong's reign, and in an alliance of power, both cleared the court of any opposition against them and controlled everything, but at the end of Emperor Suzong's reign, both became enemies. In 762, with Emperor Suzong gravely ill, Li Fuguo killed Empress Zhang in a power struggle and shortly after that, Emperor Suzong died.
He was succeeded by his son Emperor Daizong, who was eventually able to kill Li Fuguo, but the tradition of eunuchs in power had started. Suzong's death on 16 May came only 13 days after the death of his father, the Emperor Xuanzong.
Background Li Sisheng was born in 711, during the second reign of his grandfather Emperor Ruizong, as the third son of his father, then the Crown Prince, Li Longji, who would later become Emperor Xuanzong. His mother Consort Yang Guipin (posthumously Empress Yuanxian) was from the imperial clan of the preceding Sui dynasty.
Her great-grandfather Yang Shida () was a high-level official during Sui and had been given the title Prince of Zheng (). Her father Yang Zhiqing () was a general of the imperial guards during Tang. When Consort Yang Guipin was pregnant with Li Sisheng, Li Longji was locked in a power struggle with his aunt, Emperor Ruizong's sister Princess Taiping, and it was said that Princess Taiping had placed many associates in the crown prince's palace to spy on Li Longji and that she did not want him to have many sons. He already had two by that point—Li Sisheng's older brothers Li Sizhi, later named Li Cong (by Consort Liu), and Li Siqian, later named Li Ying (by Consort Zhao).
Li Longji was worried that, if Princess Taiping found out that Yang Guipin was pregnant, Princess Taiping's associates might harm him, and he spoke to a close associate, Zhang Yue, stating: "A powerful individual did not want me to have many sons. I am afraid that this woman would become a target. What do you think?" Li Longji began to prepare an herbal stew that, in traditional Chinese medicine, was believed to be able to induce an abortion, but as he did so, fell asleep and had a dream that a god descended and overturned the ding holding the stew. When he told Zhang this as well, Zhang responded, "This is heaven's will. You should not worry."Old Book of Tang, vol. 52. As a result, later on in life, Li Sisheng would feel personally indebted to Zhang Yue.Zizhi Tongjian, vol. 220.
In 712, Emperor Ruizong passed the throne to Li Longji, who took the throne as Emperor Xuanzong, but Emperor Ruizong retained actual power as Taishang Huang (retired emperor). Shortly after Emperor Xuanzong took the throne, Emperor Ruizong, as retired emperor, was the one who created Li Sisheng the Prince of Shan.
After Emperor Xuanzong suppressed Princess Taiping's associates in 713 and forced her to commit suicide, Emperor Ruizong transferred imperial authorities to Emperor Xuanzong and was no longer involved in politics. Li Siqian, whose mother Consort Zhao was then Emperor Xuanzong's favorite concubine, was created crown prince. Li Sisheng, although his mother was alive, was raised by Emperor Xuanzong's wife Empress Wang, who was herself sonless.
It was said that in his childhood, he was kind and studious, and Emperor Xuanzong was pleased with him. Emperor Xuanzong thus made the officials He Zhizhang (), Pan Su (), Lü Xiang (), Huangfu Bin (), and Xing Su () accompany him in his studies.
In 724, due to the machinations of Consort Wu, who had by then become Emperor Xuanzong's favorite concubine, Empress Wang was deposed, and she died shortly after.Old Book of Tang, vol. 51. Thereafter, Consort Wu began a campaign, in association with the chancellor Li Linfu, to have her own son Li Qing, the Prince of Shou, made crown prince, but was not able to succeed initially. Meanwhile, in 726, Li Sisheng's title was changed to the Prince of Zhong, and his name was changed to Li Jun. In 728, his own mother Consort Yang Guipin died.
In 729, when there was a Khitan and Kumo Xi incursion, Li Jun was put in titular command of the army sent to repel the Khitan and the Xi, with Emperor Xuanzong's second cousin Li Hui (), the Prince of Xin'an, in actual command of the army. After Li Hui defeated the Khitan and the Xi, Li Jun was nevertheless rewarded with the honorific title of Situ (), one of the Three Ducal Ministers. In 735, his name was changed to Li Yu.
In 737, due to the machinations of Consort Wu, Li Ying, along with his brothers Li Yao (), the Prince of E, and Li Ju (), the Prince of Guang, was accused of crimes, deposed, and forced to commit suicide. Consort Wu and Li Linfu continued to lobby for Li Qing (whose name had been changed to Li Mao at this point) to be created crown prince, but with Consort Wu having died herself later in 737 and Emperor Xuanzong believing that Li Yu was capable, he hesitated.
At the urging of the eunuch Gao Lishi, who believed that one of his older sons should be made crown prince, Emperor Xuanzong made Li Yu crown prince on 24 June 738（[开元二十六年]六月庚子，立忠王玙为皇太子。）Jiu Tang Shu, vol.09 and renamed him Li Shao. As it was quickly pointed out that he thus shared a name with the Liu Song crown prince Liu Shao, who killed his father and usurped the throne, his name was then quickly changed to Li Heng and would not change again thereafter. One of his consorts, Consort Wei, the sister of the official Wei Jian (), was created crown princess.
As crown prince
As Li Heng's ascension to be crown prince was against Li Linfu's wishes, and also because Wei Jian, who drew favor from Emperor Xuanzong due to his abilities to increase revenues for the imperial treasury, was becoming a rival to Li Linfu at court, Li Linfu looked for ways to incriminate both Wei and Li Heng. In 746, when the official Yang Shenjin (), at Li Linfu's instigation, reported to Emperor Xuanzong that, one night, Li Heng met Wei while both were sightseeing, and shortly after, Wei met a friend of his, the general Huangfu Weiming () at a Taoist temple, Li Linfu used these incidents to accuse Wei and Huangfu of secretly pledging allegiance to Li Heng and planning to remove Emperor Xuanzong to replace him with Li Heng.
Wei and Huangfu were arrested and interrogated by Yang, Wang Hong (), and Ji Wen (), but Emperor Xuanzong, who did not want the case to further explode into a major incident although he believed Li Linfu's accusations, demoted Wei and Huangfu out of the capital and, for the time being, stopped the investigation. However, when Wei Jian's brothers Wei Lan () and Wei Zhi () submitted a defense of their brother Wei Jian later in 746—and the defense cited words from Li Heng—Emperor Xuanzong was incensed.
Li Heng, in fear, divorced Crown Princess Wei and asked for the Wei brothers to be punished. The Wei brothers, along with a number of their associates—including the former chancellor Li Shizhi, Wei Bin (), Wei Jian's nephew Li Quan () the Prince of Xue, Pei Kuan (), and Li Qiwu (), were all demoted. (In 747, at Li Linfu's instigation, the Wei brothers, Huangfu, and Li Shizhi were all forced to commit suicide.)
Later in 746, yet another incident again nearly brought disaster to Li Heng. One of Li Heng's other consorts, Consort Du, was a daughter of the official Du Youlin (). Consort Du's brother-in-law Liu Ji () had a dispute with the Du family and falsely accused them of using witchcraft in favor of Li Heng. Li Linfu had Ji Wen interrogate Liu, and Ji implicated Liu in the alleged plot as well. Du Youlin, Liu, and Liu's friend Wang Zeng () were all caned to death, and Li Heng felt compelled to expel Consort Du from the household as well. Li Linfu also used this case to have two other officials friendly with Liu, Li Yong () and Pei Dunfu (), executed by caning.
In 747, when one of Emperor Xuanzong's favorite generals, An Lushan, visited the capital Chang'an to pay respect to Emperor Xuanzong, An, who was not Han, initially refused to bow to Li Heng—pretending that he was only loyal to Emperor Xuanzong and to no one else, including the crown prince, and that he did not even know what a crown prince was.
Only after Emperor Xuanzong explained what a crown prince is—the reserve emperor, to succeed him later—was An willing to bow to Li Heng. This caused Emperor Xuanzong to favor An even more, but also later caused An to be apprehensive of whether Li Heng would bear continued resentment toward him over the incident.
Later in 747, Li Linfu tried to use yet another case to undermine Li Heng. The general Wang Zhongsi, who was raised with Li Heng inside the palace because his father Wang Haibin () had died in battle in service to the empire, was accused of interfering with the campaign of another general, Dong Yan'guang (), against Tibetan Empire.
Li Linfu broadened the accusation to an accusation that Wang was planning to start a coup to overthrow Emperor Xuanzong and replace him with Li Heng. At the intercession of another general, Geshu Han, however, Wang was spared from death, and Li Heng was not implicated. It was said that during this time period, Li Linfu made other attempts to undermine Li Heng, but with Gao Lishi and Zhang Shuo's son Zhang Ji (), who had married Li Heng's sister Princess Ningqing, protecting Li Heng, Li Heng escaped unharmed each time.
As of 754, the chancellor in power was Yang Guozhong (Li Linfu having died in 752), the cousin of Emperor Xuanzong's then-favorite concubine Yang Guifei (unrelated to Li Heng's mother). Yang Guozhong and An were locked in a power struggle, and Yang repeatedly accused An of plotting a rebellion, but Emperor Xuanzong would not believe it, although Li Heng eventually came to agree with Yang Guozhong.
In late 755, with Yang Guozhong repeatedly trying to provoke An into a rebellion, An finally did, from his base at Fanyang (范陽, in modern Beijing). After the rebellion started, Emperor Xuanzong briefly considered making Li Heng regent, but at the pleas of Consort Yang and her three sisters (who were fearful that Li Heng would act against them if he had regent powers), did not actually do so.
By summer 756, An had declared a new state of Yan as its emperor, and his forces were approaching Chang'an.
On July 14, 756,According to Tang Xuanzong's biography in the Old Book of Tang, he abandoned Chang'an in the early hours of the yiwei day in the 6th month of the 15th year of the Tianbao era of his reign. This corresponds to 14 Jul 756 in the Gregorian calendar.(「(天宝十五载六月)乙未，凌晨自延秋门出，...」) Old Book of Tang, vol. 9. Emperor Xuanzong, with Yang Guozhong suggesting that they flee to Jiannan Circuit (劍南, headquartered in modern Chengdu), abandoned Chang'an and fled with Gao Lishi, Yang Guozhong, Wei, Li Heng, Consort Yang, and her family. The following day, July 15, the imperial guards accompanying the emperor, angry at Yang Guozhong, rose at Mawei Station (馬嵬, in modern Baoji, Shaanxi) and killed him and forced Emperor Xuanzong to kill Consort Yang as well.