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.
Lu Wan
In the winter of 202 BC, after Liu Bang defeated Xiang Yu at the Battle of Gaixia, he ordered Lu Wan and Liu Jia (劉賈) to lead troops to attack Gong Wei, the King of Linjiang (臨江王). They defeated Gong Wei, conquered Linjiang, and returned by the seventh month of that year. Lu Wan later followed Liu Bang to attack Zang Tu, the King of Yan (燕王), who was defeated. By then, Liu Bang had unified most – if not all – of the Eighteen Kingdoms under his control and established the Han Empire with himself as its first ruler; he is historically known as "Emperor Gao" (or Emperor Gaozu) of the Han dynasty. Although he had already awarded vassal king titles to seven men who were not from the Liu clan, he wanted to make Lu Wan a vassal king as well so he sought his subjects' opinions. They were aware of the emperor's intention, so they nominated Lu Wan on the grounds that he had made great contributions in the military campaigns against the rival kingdoms. In the eighth month of 202, Lu Wan was formally enfeoffed as the "King of Yan".