Tanshihuai’s Xianbei confederation

The Xianbei, a people of the eastern steppe, moved into Mongolia after the Northern Xiongnu state collapsed in 89–91, and more than 100,000 Xiongnu tents that stayed behind took the Xianbei name. According to the Book of the Later Han, Tanshihuai — whose mother claimed she had conceived him by swallowing a hailstone — won renown as a youth by riding alone after raiders and recovering his maternal family’s herds, and was chosen chief (daren) for his fair judgements. He set up his court at Mount Danhan, more than 300 li north of the Han frontier town of Gaoliu (probably in present-day Shangyi County, Hebei), and the chiefs of the east and west submitted to him. He repelled the Dingling in the north and the Fuyu in the east, attacked the Wusun in the west and held all the former Xiongnu lands, said to measure 14,000 li from east to west. He divided the realm into three parts — from Liaodong to Youbeiping, from Youbeiping to Shanggu, and from Shanggu to Dunhuang and the Wusun — each under chiefs subject to him.

His raids began in 156 with 3,000–4,000 horsemen against Yunzhong; in 166 the Xianbei, together with the Southern Xiongnu and the Wuhuan, sent tens of thousands of horsemen into nine frontier commanderies. Emperor Huan’s court offered him a royal seal and a marriage alliance, but he refused, and after Emperor Ling’s accession (168) hardly a year passed without Xianbei raids on the northern frontier. In 177 the court official Cai Yong, arguing against a counter-offensive, warned that the Xianbei held all the old Xiongnu lands, could field 100,000 warriors, had obtained good iron and had Han fugitives as their advisers. The emperor overruled him: three columns of 10,000 horsemen each under Xia Yu, Tian Yan and Zang Min marched more than 2,000 li into the steppe, the chiefs of Tanshihuai’s three divisions routed them, and the generals fled back with a few dozen riders each. According to the Book of the Later Han, seven or eight men in ten were lost; the Wei shu quoted in the commentary to the Records of the Three Kingdoms says only one in ten returned.

The confederation rested on Tanshihuai’s personal authority. The Book of the Later Han says only that he died in the Guanghe era (178–184), aged 45 (the Wei shu gives the same age); the Zizhi tongjian places his death in 181. His son Helian lacked his father’s ability and half of the tribes deserted him; after Helian was killed raiding the Han frontier, the Xianbei split among rival chiefs.