section_path: Government and politics/Kingdoms and marquessates
section_name: Kingdoms and marquessates
paragraph_text: Kingdoms and marquessates
  
  Kingdoms—roughly the size of commanderies —were ruled exclusively by the emperor's male relatives as semi-autonomous fiefdoms. Before 157 BC, some kingdoms were ruled by non-relatives, granted to them in return for their services to Emperor Gaozu. The administration of each kingdom was very similar to that of the central government. Although the emperor appointed the Chancellor of each kingdom, kings appointed all the remaining civil officials in their fiefs.
  
  However, in 145 BC, after several insurrections by the kings, Emperor Jing removed the kings' rights to appoint officials whose salaries were higher than 400 bushels. The Imperial Counsellors and Nine Ministers (excluding the Minister Coachman) of every kingdom were abolished, although the Chancellor was still appointed by the central government.
  
  With these reforms, kings were reduced to being nominal heads of their fiefs, gaining a personal income from only a portion of the taxes collected in their kingdom. Similarly, the officials in the administrative staff of a full marquess's fief were appointed by the central government. A marquess's chancellor was ranked as the equivalent of a county prefect. Like a king, the marquess collected a portion of the tax revenues in his fief as personal income.
  
  Until the reign of Emperor Jing of Han, the Han emperors had great difficulties controlling their vassal kings, who often switched allegiances to the Xiongnu whenever they felt threatened by imperial centralization of power. The seven years of Gaozu's reign featured defections by three vassal kings and one marquess, who then aligned themselves with the Xiongnu. Even imperial princes controlling fiefdoms would sometimes invite a Xiongnu invasion in response to the Emperor's threats. The Han moved to secure a treaty with the Xiongnu, aiming to clearly divide authority between them. The Han and Xiongnu now held one another out as the "two masters" with sole dominion over their respective peoples; they cemented this agreement with a marriage alliance (heqin), before eliminating the rebellious vassal kings in 154 BC. This prompted some of the Xiongnu vassals to swap allegiances to the Han, starting in 147. Han court officials were initially hostile to the idea of disrupting the status quo by expanding into Xiongnu territory in the steppe. The surrendered Xiongnu were integrated into a parallel military and political structures loyal to the Han emperor, a step toward a potential Han challenge to the superiority of Xiongnu cavalry in steppe warfare. This also brought the Han into contact with the interstate trade networks through the Tarim Basin in the far northwest, allowing for the Han's expansion from a regional state to a universalist, cosmopolitan empire achieved in part through further marriage alliances with the Wusun, another steppe power.