Campaign against Yuan Shu

The campaign against Yuan Shu was a punitive expedition that took place between 197 and 199 in the late Eastern Han Dynasty. The campaign was initiated by the Han government against the Zhong Dynasty of Yuan Shu, after Yuan declared himself "Son of Heaven", an act perceived as treason against Emperor Xian, the nominal Han ruler. The campaign concluded with the defeat of Yuan Shu and collapse of the Zhong regime.

Background
The Imperial Seal, a symbol of the Emperor's authority, was lost in Luoyang when Dong Zhuo ravaged the city. Sun Jian, a member of the coalition against Dong Zhuo found the Imperial Seal by chance in the ruins of Luoyang and kept it for himself. Sun Jian was a general under Yuan Shu at this time, so when Yuan heard that Sun had acquired the Seal, he held Sun's wife hostage and forced Sun to pass the Seal to him.

Around 196, when Sun Jian's son and successor Sun Ce was attacking territories in Jiangdong, Yuan Shu perceived his control over southern China as secure. In early 197, he hurriedly declared himself a "Son of Heaven" (i.e. Emperor), starting a new Zhong (仲) dynasty in Huainan. Yuan Shu's action was viewed as treason against the Han emperor, causing Sun Ce to break ties with him which may have given other warlords a reason to attack his regime. The imperial court, which was under Cao Cao's control then, issued edicts to Sun Ce and Lü Bu, urging them to take aggressive action against Yuan Shu.

The campaign
Upon receiving news that Yuan Shu had declared himself a "Son of Heaven", Sun Ce sent letters to his uncle Wu Jing and cousin Sun Ben, who both served under Yuan Shu, as an administrator and general, respectively, asking them to sever relations with him. Both Wu Jing and Sun Ben responded to Sun Ce's call and defected to him. As a consequence, Yuan Shu lost Guangling and the territories conquered by Sun Ce in Jiangdong, dramatically reducing his influence in southern China. Meanwhile, Lü Bu defeated Yuan Shu's forces at the north of the Huai River and pillaged the area. In an effort to turn the tide, Yuan Shu sent an army to invade Chen, but was defeated by Han forces led by Cao Cao. Yuan Shu then relocated his base to south of the Huai River.

When Yuan Shu's influence had been reduced to a minimal, internal conflict arose among the members of the alliance formed against him. Lü Bu, upon request from Yuan Shu, attacked Liu Bei, who received support from Cao Cao to fight back. The conflict led to the Battle of Xiapi in 198, fought between the allied forces of Cao Cao and Liu Bei against Lü Bu. Facing a dire situation, Lü Bu turned to Yuan Shu for aid. Yuan Shu sent only about 1,000 cavalry to reinforce Lü Bu, but the force was defeated before it reached Xiapi. As Lü Bu's downfall seemed inevitable, Yuan Shu sent messengers to incite the Shanyue tribes and bandit leader Zu Lang to attack Sun Ce. Sun Ce defeated the enemy and continued to strengthen his influence in Jiangdong.

On the other hand, Yuan Shu's was faring badly; his treasury was empty and his military was too weak to resist an invasion or suppress a rebellion. As a result, Yuan Shu opted to incinerate his palace complexes and escape to the Qian hills, where two of his former followers, Lei Bo and Chen Lan, were currently hiding. However, Lei Bo and Chen Lan refused to accept Yuan Shu, so Yuan Shu wrote to his clansman Yuan Shao, promising to give Yuan Shao the Imperial Seal if the latter would help him. In response, Yuan Shao dispatched his son, Yuan Tan, to escort Yuan Shu to Qing Province (covering present-day Shandong). Cao Cao sent Liu Bei and Zhu Ling to intercept Yuan Shu while Yuan was en route to Qing Province, so Yuan had no choice but to turn back to Huainan. Yuan Shu eventually died of illness on the way back to his capital Shouchun.

Aftermath
Yuan Shu's family went to rely on Yuan Shu's former follower Liu Xun, while his other followers Yang Hong and Zhang Xun planned to surrender to Sun Ce, but Liu Xun had them captured and held in Lujiang. In 199, Sun Ce defeated Liu Xun and conquered Lujiang, freeing Yuan Shu's family and men.

Modern references
The campaign is featured in the sixth and seventh instalments of the video game series Dynasty Warriors produced by Koei.