Kings of the Han dynasty
The kings from other dynasties (, "yìxìng wáng") were mostly remnants of the rebellion against the Qin dynasty. Following the Dazexiang Uprising, many noblemen rose in rebellion. Heirs, pretenders, and warlords called themselves "kings" and claimed sovereignty as continuations of the six states previously suppressed by Qin. Among these, Chu was the most powerful. However, its rightful ruler Huai II was assassinated on the orders of the warlord Xiang Yu and the 18 Kingdoms Xiang had formed rose in rebellion against him. Liu Bang, king of Han, ultimately defeated Chu and established the new Han dynasty. The kings who had sided with him were then permitted to maintain their titles and lands. A few other kingdoms were also formed by Liu Bang for generals and favorites.
History of the Han dynasty
The half-Chinese, half-Xiongnu noble Yituzhiyashi (伊屠智牙師), son of Huhanye Chanyu and Wang Zhaojun, became a vocal partisan for Han China within the Xiongnu realm; Bielenstein claims that this led conservative Xiongnu nobles to anticipate a break in the alliance with Han. The moment came when Wang Mang assumed the throne and demoted the Chanyu to a lesser rank; this became a pretext for war. During the winter of 10–11 CE, Wang amassed 300,000 troops along the northern border of Han China, a show of force which led the Xiongnu to back down. Yet when raiding continued, Wang Mang had the princely Xiongnu hostage held by Han authorities executed. Diplomatic relations were repaired when Xian (咸) (r. 13–18 CE) became the chanyu, only to be soiled again when Huduershi Chanyu (呼都而尸) (r. 18–46 CE) took the throne and raided Han's borders in 19 CE.