An Lushan rebellion

The An Lushan rebellion was an eight-year civil war (from 755 to 763 AD) during the mid-point of the Tang dynasty that started as a commandery rebellion against the Imperial Government, attempting to overthrow and replace it with the rogue Yan dynasty. The more commonly referred term Ān-Shǐ is used to recognize the two families that led the rebellion, originally by An Lushan, a fangzhen (a system of autonomous military districts during Medieval China) general officer and jiedushi of the Taiyuan Commandery who 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 to An Lushan, violently usurped the leadership and killed An Qingxu. Shi Siming ruled for two years, but in turn fell victim to patricide by his own son Shi Chaoyi, who ruled for another two years before the rebellion was finally quelled by Tang loyalists. The rebellion is also known in Chinese historiography either as the An–Shi rebellion, An–Shi Disturbances (simplified Chinese: 安史之乱; traditional Chinese: 安史之亂; pinyin: Ān Shǐ zhī luàn) or Tianbao Chaos (天寶之乱).

The rebellion began in the 14th year of the Tianbao era (755 AD), and its overt phase began on December 16 (November 9 on the traditional lunisolar calendar) when An Lushan mobilized his army and marched to Fanyang, and ended when the Yan dynasty fell on 17 February, 763 AD (although the extended effects lasted past this), spanning the reigns of three Tang emperors (Emperor Xuanzong, Suzong and Daizong). 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 combat deaths caused significant population loss from famine, population displacements and large-scale infrastructure destruction, significantly weakening the Tang dynasty, collapsing the prestige of the Tang emperors as the Khan of Heaven and leading to the permanent loss of the Western Regions. It was a direct cause of Tang dynasty's decline, and led to rampant regional warlord secessionism during the latter half of the dynasty that continued into the Five Dynasties and Ten Kingdoms period for nearly a century after Tang's demise, and 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 then been a political and economic heartland of China at least since the Han dynasty, and the economic center of China had shifted towards the Jiangnan region afterwards.