Course of the Event
The Kaiyuan era of prosperity did not arise in isolation. Emperor Taizong of Tang’s Zhenguan era of good government had laid important institutional foundations, and although politics remained turbulent at times under Emperor Gaozong and Wu Zetian, the social economy continued to develop and systems such as the equal-field system of land distribution and taxation and the Fubing system still functioned. After Wu Zetian’s abdication, however, the Tang entered a brief period of political disorder. Wu Sansi allied with Empress Wei and Princess Anle and successively eliminated the “Five Princes.” Crown Prince Li Chongjun raised troops and killed Wu Sansi and Wu Chongxun, but was himself killed by Empress Wei’s followers. Empress Wei and Princess Anle later conspired to poison Emperor Zhongzong of Tang, Li Xian, installed Li Chongmao as a puppet young emperor, and dominated the court; Princess Anle openly sold offices, and government became corrupt.
In the sixth lunar month of 710, the fourth year of Jinglong, Li Longji, the third son of Li Dan, then Prince of Xiang, joined his aunt Princess Taiping in launching a palace coup. Their forces entered the palace, killed Empress Wei, Princess Anle, and Wu Yanxiu, eliminated the Wei–Wu faction, and brought Li Dan in to assist the young emperor before enthroning him as Emperor Ruizong of Tang. In 712, the third year of Jingyun, Emperor Ruizong abdicated in favor of Li Longji, who became Emperor Xuanzong. Princess Taiping now changed from ally to rival; the source notes that four of seven Grand Councilors came from her circle and that more than half of civil and military officials were attached to her. In the seventh lunar month of 713, the first year of Kaiyuan, Emperor Xuanzong learned of an alleged plan by Princess Taiping and struck first, executing her followers Chang Yuankai, Li Ci, Xiao Zhizhong, and Cen Xi. Dou Huaizhen committed suicide, and Princess Taiping was ordered to die at home.
After suppressing Princess Taiping’s faction, Xuanzong immediately held a grand military review below Mount Li, mobilizing two hundred thousand troops whose banners were said to stretch more than fifty li. He exiled Guo Yuanzhen and executed Tang Shao to demonstrate imperial authority, and gradually sent meritorious officials and princes out of the capital to serve as provincial inspectors. Once imperial power was secure, he began a broader reorganization of government.
Emperor Xuanzong regarded the selection of officials as fundamental to good government. In early Kaiyuan he carefully chose Yao Chong, Lu Huaishen, Song Jing, Su Ting, Zhang Jiazhen, and Yuan Qianyao as Grand Councilors, all known for administrative ability and diligence. Yao Chong became famous for his “Ten Essential Proposals,” which addressed contemporary problems, while Song Jing was known for integrity and forthright remonstrance. Relying on these officials, Xuanzong stabilized politics while developing the economy.
Institutionally, Xuanzong strengthened remonstrance offices and restored channels for criticism. He revised legal codes, statutes, administrative regulations, and ordinances and oversaw compilation of the *Tang Liudian*. The *Tang Liudian* is described in the source as the earliest surviving Chinese administrative code, detailing central and local institutions, staffing, and official responsibilities, and it had a lasting influence on later administrative codification.
Economically, the government sought to curb powerful aristocratic households, release labor, reform the system of tax-exempt fiefs, increase state revenue, and reduce burdens on ordinary people. It also restricted Buddhist institutions and promoted agriculture. In the eighth lunar month of 714, the second year of Kaiyuan, officials were ordered to review Buddhist clergy nationwide, and more than twelve thousand monks and nuns judged improperly registered were forced to return to lay life. Private casting of Buddhist images and copying of scriptures were also restricted. Four government directorates supervised official handicraft production, while private handicrafts developed rapidly. Commerce prospered, early financial houses appeared, and border markets and overseas trade expanded.
Tang military power achieved major victories during Kaiyuan. In the tenth lunar month of 714, Xue Ne defeated the Tibetan Empire at Wujie Post on the western border of Weizhou and reportedly took seventeen thousand heads. In the sixth lunar month of 716, Qapaghan Qaghan was killed and his head sent to Chang’an; five groups, including the Uyghurs and Pugu, submitted to Tang. In 722, the tenth year of Kaiyuan, Mai Thúc Loan in Annam raised an army said to number one hundred thousand against Tang. Grand General of Agile Cavalry Yang Sixu led forces to suppress the revolt and killed Mai Thúc Loan. In the same year, when the Tibetan Empire invaded Lesser Bolü, Zhang Song, Military Commissioner of Beiting, dispatched Zhang Sili from Shule with four thousand Tang troops, defeating the Tibetan force and reportedly killing tens of thousands. In 729, the seventeenth year of Kaiyuan, Li Yi, Prince of Xin’an and Military Commissioner of Shuofang, captured the Tibetan stronghold of Shibao and extended the frontier by more than one thousand li. In 732, the twentieth year of Kaiyuan, he defeated Xi and Khitan forces and presented prisoners at the eastern capital.
In the tenth lunar month of 725, the thirteenth year of Kaiyuan, Emperor Xuanzong departed the eastern capital for Mount Tai to perform the feng and shan sacrifices. Civil and military officials, imperial relatives, and chiefs from non-Tang peoples accompanied him; the source describes people and livestock covering the countryside for dozens of li around each halt and state supply trains continuing for hundreds of li. The feng and shan sacrifices were among the highest ritual expressions of successful imperial rule and were taken to symbolize the peak of Xuanzong’s civil and military achievements. After returning to the eastern capital, he held a banquet for the court at Guangda Tower, and Su Ting commemorated the occasion in a court poem.
In 734, the twenty-second year of Kaiyuan, Pei Yaoqing reformed grain transport, placing granaries where the Yellow River and Bian River routes met and organizing shipment in stages, greatly improving transport efficiency. In 736, the twenty-fourth year, Zhang Jiuling was removed as Grand Councilor and Li Linfu gradually dominated the court. Government began to deteriorate. Li Linfu excluded rivals and restricted channels of remonstrance, while Xuanzong gradually lost the sharp political judgment of his earlier reign.
In 737, the twenty-fifth year of Kaiyuan, Li Linfu promoted political and military changes. Privately recruited frontier troops were recognized as large bodies of professional soldiers, described as long-service fighting men, bringing the Fubing system to an end. Military specialization was also extended by allowing commanders with particular frontier experience, including non-Han generals, to serve for long periods as Military Commissioners. These changes helped carry Tang military power to another high point: Tang and the Uyghurs destroyed the Second Turkic Khaganate in the north; An Lushan fought the Khitan in the northeast; Tang weakened the Türgesh and dominated the Western Regions; and Geshu Han inflicted major defeats on the Tibetan Empire in the west. At the same time, the Military Commissioners accumulated rapidly expanding power, laying an institutional basis for the later An Lushan Rebellion.