After Liu Bang defeated Xiang Yu and proclaimed himself emperor of the Han dynasty, he followed the practice of Xiang Yu and enfeoffed many generals, noblemen, and imperial relatives as kings (), the same title borne by the sovereigns of the Shang and Zhou dynasties and by the rulers of the Warring States. Each king had his own semi-autonomous kingdom. This was a departure from the policy of the Qin dynasty, which divided China into commanderies governed by non-hereditary governors. The kings were divided into two groups: yìxìng wáng, literally "kings of different surnames", and tóngxìng wáng, literally "kings of the same surname", i.e., the imperial surname Liu. The yixing wang represented an obvious threat to the Han empire, and Liu Bang and his successors suppressed them as quickly as was practical: they had disappeared by 157 BC. The tongxing wang were originally left to their own devices but, after the Rebellion of the Seven States in 154 BC, their independence was curtailed. Eventually they lost most of their autonomy. For this reason, the title is also translated as "prince" when referring to later kings of the dynasty, to reflect both their link to the ruling house and the vestigial nature of the former vassal kingdoms. Yixing Kingdoms The kings from other dynasties () 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. Although nominally under the rule of the Han, these kings were de facto independent and held considerable power within their territories, which could span several prefectures. As these kingdoms proved unruly, Liu Bang gradually subdued them through conspiracies, wars, and political maneuvering. Many were thus deposed and their kingdoms annexed by Han. As he was dying, the emperor ordered his ministers to swear an oath that only members