Sima Xun

Sima Xun was the great-great-grandson of Sima Xún (司馬恂), a brother of Sima Yi. He was living in Chang'an prior to 316, when the city fell to Han Zhao forces led by Liu Yao that year. Liu Yao's general, Linghu Ni discovered Sima Xun and decided to make him his son. By the time he became an adult, he excelled at horse riding and archery. Han Zhao fell in 329 and Liu Yao was killed by his rival Shi Le of Later Zhao. Sima Xun remained in the north for a while but in 331, he fled south to Jiankang, where his other family members had already established a new dynasty a few years back. He was welcomed and appointed as the Supervisor of the Internuncios.[1]

In 336, Sima Xun was sent to Hanzhong to populate the region with Jin subjects. However, the emperor of Cheng Han, Li Shou attacked and routed him.[2] By 344, he was serving as Yu Yi's Army Advisor when the Inspector of Liangzhou, Huan Xuan passed away, so Yu Yi appointed Sima Xun as the Inspector of Liangzhou.

Jin's northern rival, Later Zhao, entered a speedy decline in 349 after the death of its emperor, Shi Hu. His successor, Shi Shi, was removed through a coup by his brother Shi Zun. Shi Zun's coup sparked a number of rebellions from the other princes, so the Jin dynasty decided to take advantage of the state's vulnerability. One prince, Shi Bao (石苞), was noted for his incompetence and was planning to attack Shi Zun, so the people of Yongzhou asked for Sima Xun to accept their surrender.[3]

Sima Xun marched through the Luo Valley (駱谷; southwest of present-day Zhouzhi County, Shaanxi) and captured Changcheng before sending his general Liu Huan to capture the ancient capital of Chang'an, and while doing so, Liu Huan captured Hecheng (賀城, in present-day Zhouzhi County, Shaanxi). The people around the region killed the Zhao administrators and welcomed the Jin forces. Shi Bao called off his plans to overthrow Shi Zun and sent Ma Qiu and a few others to repel him. Shi Zun also sent Wang Lang to help Sima Xun, and Xun, feeling that the Zhao forces outnumbered him, decided to retreat instead. He did however captured the city of Wancheng from Zhao before returning to his base in Liangzhou.[4]

Zhao continued to deteriorate as Ran Min took over the government later in 349. In 351, Former Qin forces drove out Du Hong (杜洪) and Zhang Ju (張舉) from the Guanzhong region. The two men called Sima Xun for assistance, so he marched north again. Qin's ruler, Fu Jian met his forces at Wuzhang Plains, where Sima Xun was repeatedly defeated. Sima Xun eventually forfeited and retreated to Nanzheng.[5]

Meanwhile, Du Hong wanted to kill Zhang Ju for mistreating him, so he successfully persuaded Sima Xun to kill him. In 352, Sima Xun pretended to invite Zhang Ju to meet him before killing him. Zhang Ju's brother, whose name was not recorded, attacked Sima Xun, but the two agreed to a truce and Sima Xun returned south[6] (some sources differ by saying that Zhang Ju was actually killed by Fu Jian, not Sima Xun[7]). Later that year, Sima Xun helped in the suppression of Xiao Jingwen's (蕭敬文) rebellion in Fucheng.

In 356, the prominent Jin general, Huan Wen was about to launch his first northern expedition in collaboration with Sima Xun and Former Liang. Sima Xun marched through Ziwu Valley (子午谷; east of present-day Yang County, Shaanxi) and captured Chencang together with Liang's general Wang Zhuo. Huan Wen defeated the Qin forces at the Battle of Bailu Plains, so the Qin commander Fu Xiong shifted his focus in retaking their western regions. Fu Xiong routed Sima Xun, causing him to retreat to Fort Nüwa (女媧堡). Fu Xiong then returned to Bailu Plains, where this time he defeated Huan Wen and forced him to turn back. Sima Xun faced Fu Xiong again at Chencang and was defeated once more, leading to his retreat and ending the expedition in failure.[8]

Sima Xun remained in Liangzhou for another decade, ensuring his control over the region. Sima Xun was reputed for his harsh and cruel administration. He was prone in killing his critics, and had intentions to break away from the dynasty in Liangzhou. However, his main concern was the Inspector of Yizhou, Zhou Fu, but with his death in late 365, Sima Xun began making preparations. His officers, Yong Duan (雍端) and Kui Cui (隗粹) were against this but Sima Xun had them both killed. He declared himself Governor of Liangzhou and Yizhou and the King of Chengdu before attacking Fucheng. The city was abandoned by Guanqiu Wei (毌丘暐), so Sima Xun captured it easily before marching on to Chengdu and besieging Zhou Chu (周楚).[9]

Huan Wen responded by sending his general, Zhu Xu to lift the siege. Although Sima Xun's position had always worried Huan Wen, the rebellion only lasted for a few months. In early 366, Zhu Xu and Zhou Chu had already defeated Sima Xun. They sent him to Huan Wen, who in turn sent him to Jiankang, where he was beheaded along with his officers.[10]

• Fang, Xuanling (ed.) (648). Book of Jin (Jin Shu).
• Sima, Guang (1084). Zizhi Tongjian.