Xiantian era (712–713) Emperor Xuanzong made his wife
Crown Princess Wang empress. Meanwhile, Princess Taiping continued to be listening to politics with curtains in the court, highly extremely influential in governmental matters through Emperor Ruizong, the group of chancellors openly frequented her house and most chancellors, forbidden troops, officials and warlords were her associates. (Of the seven chancellors at the time, five – Dou Huaizhen, Xiao Zhizhong, Cen Xi,
Cui Shi, and
Lu Xiangxian – were made chancellors at her recommendation, although Lu was not considered a member of her party.) As a result, the war between her and him continued more seriously. Liu Youqiu and the general Zhang Wei (), with Emperor Xuanzong's approval, planned to mobilize the imperial guards to kill several of those chancellors –
Dou Huaizhen,
Cui Shi and
Cen Xi. However, after Zhang told the plan to the imperial censor Deng Guangbin (), the news was leaked. At the request of Princess Taiping's, Emperor Ruizong issued an order to arrested Liu, and initially set to be executed. But Emperor Xuanzong interceded on his behalf with Emperor Ruizong, and Liu, Zhang, and Deng were spared but exiled. Emperor Xuanzong had Wang Maozhong take 300 soldiers to the imperial guard camp to behead Chang and Li Ci. Then, Jia, Li You, Xiao, and Cen were arrested and executed as well. Dou fled into a canyon and committed suicide by hanging. Xue Ji was forced to commit suicide. When Emperor Ruizong heard about this, he quickly ascended the tower at Chengtian Gate () to ascertain what was happening. Guo reported to him Emperor Xuanzong's intentions, and Emperor Ruizong felt compelled to affirm Emperor Xuanzong's actions in an edict. The next day, on 30 July, Emperor Ruizong issued an edict transferring all authorities to Emperor Xuanzong. Meanwhile, Princess Taiping, hearing what happened to her associates, fled into a temple in the mountains, only appearing three days later. Emperor Ruizong asked Emperor Xuanzong for her pardon, but he refused. Emperor Xuanzong ordered her to commit suicide at home, and put to death her sons and associates, except for Xue Chongjian. Princess Taiping's assets were confiscated, and it was said that there was so much treasure, livestock, and real estate that it took several years: more than thirty years for the accounting to be complete. Emperor Ruizong moved to a secondary palace, Baifu Hall () and would remain there until his death in 716.
Kaiyuan era (713–741) Emperor Xuanzong's
Kaiyuan era is usually viewed as one of the golden ages of Chinese history – a period of political stability, peace in society, and economic prosperity, in addition to advances in education, literature, music, painting, sculpture, and religion.
Early Kaiyuan era , 8th century original Meanwhile,
Zhang Yue and Liu Youqiu served as chancellors, but they were soon displaced by Yao Yuanzhi (who then changed his name to
Yao Chong) and
Lu Huaishen. Changing the system of having a large group of chancellors simultaneous, as had been the case throughout Tang, Emperor Xuanzong reduced the numbers to two (or sometimes three) for the rest of his reign. Yao was considered a highly capable administrator, and with him ruling on most important matters and Lu assisting, the government was said to be highly efficient. Also in 714, Emperor Xuanzong created
Li Siqian, his second son and the son of his then-favorite concubine Consort Zhao, crown prince. (Emperor Xuanzong's wife Empress Wang was sonless.) Meanwhile, Tang, the Tibetan Empire, and the
Umayyad Caliphate were constantly engaging in a three-way tug of war for influence in the
Xiyu (i.e., modern
Xinjiang and former Soviet
Central Asia) region. In 715, for example, when the king of Bahanna () was expelled by a new king supported by the Tibetan Empire and the Umayyad Caliphate, Tang forces commanded by the general () attacked the new king and restored the old king. The attack on Aksu was joined by
Turgesh Khan
Suluk. Both
Uch Turfan and
Aksu were attacked by the Turgesh, Arab, and Tibetan force on 15 August 717. Qarluqs serving under Chinese command, under Arsila Xian, a Western Turkic Qaghan serving under the Chinese Assistant Grand Protector General Tang Jiahui defeated the attack. Al-Yashkuri, the Arab commander and his army fled to Tashkent after they were defeated. , one of China's oldest
mosques, built during the reign of Emperor Xuanzong. In and around 716, there was a major locust infestation in the central China region. At Yao's suggestion, Emperor Xuanzong ordered an extensive campaign of extermination, which was said to reduce the impact of the infestation and ward off a major
famine. Later in 716, however, due to a corruption scandal involving Yao's sons and his associate Zhao Hui (), Yao incurred displeasure from Emperor Xuanzong and offered to resign. He and
Yuan Qianyao, who replaced Lu after Lu's death earlier in 716, were removed from their offices and replaced with
Song Jing and
Su Ting, with Song making more of the important decisions and Su assisting. Yao would not return to the chancellorship, but would remain influential as a key advisor for Emperor Xuanzong until Yao's death in 721. Contrary to the practical and flexible Yao, Song was more interested in emphasizing integrity and rule of law in governance, and it was said that while Yao's and Song's emphases were different, they were both regarded as instrumental in establishing the rule of
Kaiyuan and that subsequent chancellors could not compare to them.)
Middle Kaiyuan era , by
Ren Renfa (1254–1327) In 723, Zhang Jiazhen was demoted on account of a corruption scandal involving his brother Zhang Jiayou (). His position was filled by
Wang Jun, who was soon himself demoted over suspicions, never proven, that he was plotting treason. With Zhang Yue thus effectively being the senior chancellor, Zhang Yue promoted literary studies, which Emperor Xuanzong also favored. In 724, he also commissioned the chief imperial astronomer Nangong Shuo () to carry out a major astronomical survey to observe the sun and the
North Star at various points of the empire. In winter 725, Emperor Xuanzong, at Zhang Yue's urging, carried out a magnificent ceremony at
Mount Tai to offer sacrifices to heaven and earth. and permitted to maintain his title and a number of other posts. He was replaced by
Li Yuanhong on 15 May, and subsequently,
Du Xian was also added as a chancellor. Emperor Xuanzong added the general
Xiao Song as a chancellor. Subsequently, in 729, with Yuan, even though he was senior chancellor, unable to curb the disputes between Li Yuanhong and Du, Emperor Xuanzong removed all three from chancellor positions, promoting Yuwen and
Pei Guangting to be chancellors in their stead – in Yuwen's case, for his abilities to find ways to add to the imperial treasury by imposing special taxes and levies. Later in the year, though, Yuwen made false accusations against the general Li Hui () the Prince of Xin'an (Emperor Xuanzong's second cousin) and was exiled, and subsequently died in exile. Still, it was said that it was starting from Yuwen's times that Emperor Xuanzong began to pay attention on taxes to replenish the imperial treasury, which traditional historians viewed as the start of his inflicting financial burdens on the people. Further, with Pei in charge of the civil service system, it was said that due to Pei's strict adherence to seniority, the Tang civil service system began to lose its ability to find talented people to serve in offices. In 734, Emperor Xuanzong added
Li Linfu, a close associate of Consort Wu, as a chancellor as well. And he did not allow many to be set free even when they were old. As Emperor Xuanzong turned his attention to pleasure-seeking with his favorite concubine
Yang Guifei and her family, he paid less and less attention to the running of his empire, and much of his power fell into the hands of the corrupt
Li Linfu (who was succeeded by Lady Yang's dissolute cousin
Yang Guozhong) and the eunuch
Gao Lishi. At the same time, 751 saw the loss of the
Battle of Talas against the Abbasid Caliphate. As a consequence, the Tang dynasty temporarily lost some of its influence in Central Asia to the emerging Abbasid Caliphate, as several Tang tributaries turned to the Abbasids. Meanwhile, the
jiedushi (military governors), most of whom were non-
Han took more and more regional power into their own hands. Some successful generals included
Geshu Han, known for victories over the
Tibetan Empire;
Gao Xianzhi, who conquered city states of the Xiyu region, eventually battling the Abbasids at Talas; and
An Lushan who defeated and once again vassalized the Khitan. Eventually, in 755, An Lushan started the
Anshi Rebellion at
Fanyang. The rebels quickly seized the eastern capital
Luoyang, and then the imperial capital
Chang'an six months later. Emperor Xuanzong fled to
Sichuan during the war and abdicated the throne to Li Yu (whose name had been changed to Li Heng at that point) (as Emperor Suzong).
Early Tianbao era Meanwhile, at Li Linfu's encouragement, Emperor Xuanzong began to promote non-
Han generals to command large border armies, believing Li Linfu's assertion that non-Han generals were more likely to be personally loyal to Emperor Xuanzong himself and would not have clan entanglements, even though Li Linfu's own personal motivation was to prevent Han officials from going through the border command route to become chancellors, thus threatening him. Such generals who rose in ranks included
An Lushan,
An Sishun,
Geshu Han, and
Gao Xianzhi. Some were not set free even after they were over 60 years old. Meanwhile, Li Linfu was beginning to conflict with Li Shizhi and Wei Jian, who were allies. Li Linfu, who engaged a group of secret police officials to investigate and manufacture evidence against political enemies, was able to get Wei and Li Shizhi demoted and exiled in 746. (Li Shizhi was replaced by
Chen Xilie, who gained favor from Emperor Xuanzong for his knowledge in
Taoism and sorcery.) In 747, Li Linfu further carried out a campaign of terror against exiled officials, and among the officials executed were Wei, Li Yong () and Pei Dunfu (). Li Shizhi and Wang Ju, who had been instrumental in Emperor Xuanzong's initial actions against Princess Taiping, committed suicide. By 748, Consort Yang's cousins Yang Guozhong, Yang Xian () and Yang Qi (), as well as her three sisters (who were created the Ladies of Han, Guo, and Qin), had become exceedingly wealthy and powerful due to the favors that Emperor Xuanzong showed them. It was said that their wealth topped all households in Chang'an. It was also said that by 749, the empire was so wealthy that Emperor Xuanzong viewed treasures as expendable and so awarded them without limit. (1543–1590) In 755, Yang Guozhong further provoked An, who was then back at his post in Fanyang, by surrounding An's mansion at Chang'an and arresting and executing An's staff members. An, in fear and anger, rebelled in winter 755, and quickly reached and captured Luoyang after defeating
Feng Changqing's undersupplied army. Subsequently, Emperor Xuanzong, believing in reports from the eunuch Bian Lingcheng () that Feng was cowardly and that Feng's superior Gao Xianzhi was corrupt, executed both Feng and Gao and replaced Gao with Geshu in defending
Tong Pass from An's advances. An declared himself emperor of a new state of
Yan at Luoyang, but with Geshu defending Tong Pass, An's advances stalled, while Tang forces commanded by
Li Guangbi and
Guo Ziyi made advances against An-controlled territory north of the
Yellow River. Emperor Xuanzong, with Yang Guozhong suggesting that they flee to Jiannan Circuit, abandoned Chang'an and fled with Gao Lishi, Yang Guozhong, Wei, Li Heng, Consort Yang, and her family. The following day, 15 July, the imperial guards accompanying the emperor, angry at Yang Guozhong, rose and killed him and forced Emperor Xuanzong to kill Consort Yang as well. Subsequently, Emperor Xuanzong continued on to Jiannan, but Li Heng did not, but rather went to Lingwu, where, on 12 August, he recognized Emperor Suzong as the new emperor, and thereafter took the title of
Taishang Huang (retired emperor) – although his edict recognizing Emperor Suzong appeared to still indicate desire to retain control like his father Emperor Ruizong did early in his reign: However, perhaps to avoid the impression that he was keeping a rival government to Emperor Suzong, he sent the several chancellors that he had retained or created while on the journey to or after he arrived in Chengdu – Wei,
Fang Guan, and
Cui Huan – to Lingwu to formally invest imperial power on Emperor Suzong and to serve under Emperor Suzong. ==As retired emperor==