呉楚七国の乱
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.