The An Lushan rebellion was a civil war in China that lasted from 755 to 763, at the approximate midpoint of the Tang dynasty (618–907). It began as a commandery rebellion attempting to overthrow and replace the Tang government with the rogue Yan dynasty. The rebels succeeded in capturing the imperial capital Chang'an after the emperor had fled to Sichuan, but eventually succumbed to internal divisions and counterattacks by the Tang and their allies. The rebellion spanned the reigns of three Tang emperors: Xuanzong, Suzong, and Daizong.
On 16 December 755, An Lushan, the jiedushi of the Taiyuan Commandery, mobilized his army and marched to Fanyang. An Lushan led the rebellion for two years before he was assassinated by his son An Qingxu. Two years after An Qingxu's ascension, Shi Siming, the governor of Pinglu Commandery and a close ally of An Lushan, killed An Qingxu and usurped the leadership. Shi Siming ruled for two years, but was in turn killed by his own son Shi Chaoyi, who ruled for another two years until the Yan dynasty fell to Tang forces on 17 February 763. There were also other anti-Tang rebel forces, especially those in An Lushan's base area in Hebei, as well as Sogdian forces and other opportunist parties who took advantages of the chaos.
The rebellion was an important turning point in the history of medieval China, as the military activities and associated casualties caused significant depopulation from famine, displacement, and large-scale infrastructure destruction, significantly weakening the Tang dynasty and leading to the permanent loss of the Western Regions. Even though the rebellion was ultimately suppressed by a large-scale alliance between the imperial dynasty and various participants, including local militias and foreign support, the dynasty did not overall change the structure of the military committee, but only followed the old principles of establishing territory. It was a direct cause of the dynasty's decline, and led to rampant secessionism among regional warlords during the latter half of the dynasty that continued into the Five Dynasties and Ten Kingdoms period for decades after the ultimate demise of the Tang. The fear of repeating Tang's commandery secessionism also led the Song dynasty that followed to distrust and oppress prominent military commanders even when invaded by hostile foreign states such as Liao, Western Xia and Jin. It also triggered the long-term decline of the Guanzhong region, which had been a political and economic heartland of China at least since the Han dynasty, and a shift of the economic center of China towards the Jiangnan region.
Beginning in 742, Eurasia entered a 13-year period of major political turmoil, with the regional empires generally suffering "a major rebellion, revolution, or dynastic change." In this year the Second Turkic Khaganate of the eastern Eurasian Steppe was overthrown and then replaced by Sogdian-influenced Uighur rulers. This was apparently the first of several revolutionary events either led by or intimately connected with the merchants and tradespeople involved with the international commerce often referred to as the Silk Road. In 747, the Abbasids began their rebellion against the Umayyad Caliphate in Merv, Khurasan, resulting in the proclamation of a new Abbasid Caliph in about 750. This rebellion also seems to have been organized by merchants and persons identifying themselves as merchants.
The western expansion of the Tang Empire was checked in 751 by the defeat of a large expeditionary force led by General Gao Xianzhi in the Battle of Talas in the modern Fergana Valley, with the Abbasid victory attributable to the defection of the Karluk Turks in the midst of the battle. However, the Arabs did not proceed any further after the battle, and the Tang retained their Tarim Basin territory until the An Lushan rebellion.
Further, southern expansion of the Tang was limited by the ineffective, and even disastrous, campaigns against the Kingdom of Nanzhao. However, the concurrent Tang campaign against the Tibetan Empire was proceeding more successfully, with the campaign to capture the Tibetans' Central Asian territories appearing nearly successful. With the assassination of the Tibetan emperor Me Agtsom in 755 in the midst of a major rebellion within the Tibetan polity, final Tang victory over the Tibetan Empire seemed all but assured. However, back in the increasingly financially challenged Chinese heartland, the Sogdian-Turkic General An Lushan had worked himself into a position of trust with the Tang emperor Xuanzong and his consort Yang Guifei.
An Lushan was a general of uncertain birth origins, but thought to have been adopted by a Sogdian father and Göktürk mother of the Ashina tribe. Eventually he managed to become a favorite of the reigning emperor of China. His success in this regard is shown, for example, by the luxurious house Emperor Xuanzong built for him in 751, in the capital Chang'an. The house was furnished with luxuries such as gold and silver objects and a pair of ten-foot-long (3.0 m) by six-foot-wide (1.8 m) couches appliqued with rare and expensive sandalwood.
He was appointed by Emperor Xuanzong (following the suggestion of Xuanzong's favorite concubine Yang Guifei and with the agreement of Chancellor Li Linfu) to be Jiedushi of three garrisons in the north—Pinglu, Fanyang and Hedong. In effect, An was given control over the entire area north of the lower reaches of the Yellow River, including garrisons about 164,000 strong. He took advantage of various circumstances, such as popular discontent with an extravagant Tang court, the synchronous Sogdian-involved Abbasid Revolution against the Umayyad dynasty, and eventually the absence of strong troops guarding the palace coupled with a string of natural disasters. An Lushan was very influential in the Tang court, his close relationship with Emperor Xuanzong led to him being adopted by the imperial concubine Yang Guifei. The positions of power of Yang clan members (the family of the preceding Sui dynasty into which the Tang emperor had married) were important in this situation, especially complicated by the position of Yang Guifei's relative Yang Guozhong in the Tang governmental administration.
The An Lushan rebellion signaled a period of disorder spanning the reigns of three Tang dynasty emperors, beginning during the final (Tianbao era) period of the reign of Xuanzong (8 September 712 to 12 August 756), continuing through the reign of Suzong (12 August 756 to 16 May 762) and ending during the reign of Daizong (18 May 762 to 23 May 779), as well as spanning the four imperial claimants of the failed Yan dynasty.
At the end of 755 An Lushan revolted. On 16 December, his army surged down from Fanyang (near modern Beijing). Along the way, An Lushan treated surrendered local Tang officials with respect. As a result, more and more of them joined his ranks. He moved rapidly along the Grand Canal and captured the "Eastern Capital" city of Luoyang on 18 January 756, defeating the poorly supplied General Feng Changqing. There, on 5 February,^ An Lushan declared himself Emperor of the new Great Yan dynasty (大燕皇帝). His next steps would be to capture the Tang western capital of Chang'an and then to attempt to continue into southern China to complete his conquest.
However, the Battle of Yongqiu, in the spring of 756, went badly for An Lushan. Although his army, under Linghu Chao, was numerous, it was unable to make further territorial gains due to the failure to wrest control of Yongqiu (modern Qi County, Kaifeng, in Henan) and (later) the nearby Suiyang from the Tang defenders led by Zhang Xun. This prevented the Yan forces from conquering southern China, before the Tang were able to recover. The Yan army did not take control of Suiyang until after the Siege of Suiyang (January–October 757), almost two years after their initial capture of Luoyang.
Originally, An Lushan's forces were blocked from the main imperial (or "Western") capital at Chang'an (modern Xi'an), by loyal troops placed in nearly impregnable defensive positions in the intervening high mountain passes of Tongguan. Unfortunately for Chang'an, the two generals in charge of the troops at Tong Pass, Gao Xianzhi and Feng Changqing, were executed due to a court intrigue involving the powerful eunuch Bian Lingcheng. Yang Guozhong, with grossly inept military judgment, then ordered the replacement General Geshu Han, who was in charge of the troops in the passes, together with reinforcement troops, to attack An's army on open ground. On 7 July, the Tang forces were defeated. The road to the capital now lay open.