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
From its beginning, the Han imperial court was threatened by plots of treason and revolt from its subordinate kingdoms, the latter eventually ruled only by royal Liu family members. Initially, the eastern half of the empire was indirectly administered through large semi-autonomous kingdoms which pledged loyalty and a portion of their tax revenues to the Han emperors, who ruled directly over the western half of the empire from Chang'an. Gradual measures were introduced by the imperial court to reduce the size and power of these kingdoms, until a reform of the middle 2nd century BCE abolished their semi-autonomous rule and staffed the kings' courts with central government officials. Yet much more volatile and consequential for the dynasty was the growing power of both consort clans () and the eunuchs of the palace. In 92 CE, the eunuchs entrenched themselves for the first time in the issue of the emperors' succession, causing a series of political crises which culminated in 189 CE with their downfall and slaughter in the palaces of Luoyang. This event triggered an age of civil war as the country became divided by regional warlords vying for power. Finally, in 220 CE, the son of an imperial chancellor and king accepted the abdication of the last Han emperor, who was deemed to have lost the Mandate of Heaven according to Dong Zhongshu's (179–104 BCE) cosmological system that intertwined the fate of the imperial government with Heaven and the natural world. Following the Han, China was split into three states: Cao Wei, Shu Han, and Eastern Wu; these were reconsolidated into one empire by the Jin dynasty (265–420 CE).