 The next year in 201, the Xiongnu nomads—who may have been allied with Zang, although this isn't recorded—invaded Dai and forced the surrender of Han Xin, a former king of Han who had been moved into the north by the emperor and opted to make his capital at the exposed frontier town of Mayi (present-day Shuozhou in northern Shanxi) instead of at Jinying (present-day Taiyuan).Despite his long support of Liu Bang, Han came under suspicion of revolt and concluded an alliance with the Xiongnu chanyu Modu to protect himself.Learning of this arrangement, the emperor marched north in 200 and defeated Han Xin in battle; Han was able, however, to escape into exile among the nomads; and the Xiongnu were able to defeat Liu Bang's invasion of their lands at Baideng near present-day Datong.