Han conquest of Nanyue

Background

During the collapse of the Qin dynasty, Zhao Tuo established himself as the King of Nanyue in southern China. Zhao was originally a Qin military officer from Zhending in northern China. The Han frontier in the south was not threatened and there was no indication that Zhao Tuo would encroach on Han territory. In 196 BC, the Emperor Gaozu sent Lu Jia on a diplomatic mission to Nanyue to officially recognize Zhao Tuo as a local ruler. Nevertheless, relations between Han and Nanyue were sometimes strained. Zhao Tuo resented Empress Lü's ban on exports of metal wares and female livestock to Nanyue. In 183 BC, he proclaimed himself the "Martial Emperor of the Southern Yue" (南越武帝), which implied a perceived status on equal footing with the Han emperor. Two years later, Nanyue attacked the Changsha Kingdom, a constituent kingdom of the Han empire. In 180 BC, Lu Jia led a diplomatic mission to Nanyue. During negotiations, he succeeded in convincing Zhao Tuo to give up on his title as emperor and pay homage to Han as a nominal vassal.

In 135 BC, King Zhao Mo of Nanyue appealed to the Han court for help against attacking Minyue forces. The Han court responded swiftly and this led to Zhao Mo's agreement to send his son, Prince Zhao Yingqi, to serve in the palace at Chang'an. Even though Nanyue neglected to pay regular homage to the Han court, the court had its attention focused on other commitments and was not set on forcing the issue.

At the Nanyue court in 113 BC, the Queen Dowager of Nanyue, who was Han Chinese stock and married to Zhao Yingqi, suggested incorporating Nanyue as a kingdom under the suzerainty of the Han empire. At the same time, the Queen Dowager sent a letter to Emperor Wu of Han through an envoy, requesting that she be allowed to go to Chang'an to pay homage to the Han Emperor every three years, just like the internal princes of the Han dynasty, and that the border checkpoints on the border between Nanyue and Han be removed. Emperor Wu agreed to Queen Dowager's request and granted official seals to the senior officials of Nanyue. Han laws also began to be implemented in Nanyue. This formally integrated Nanyue on the same terms as the other constituent kingdoms of the Han empire.

However, many Nanyue ministers opposed unification with the Han dynasty. Lü Jia was the primary Nanyue official to oppose the idea and he led the opposition against the Queen Dowager. In 112 BC, the opposition retaliated violently and executed the Queen Dowager, a provocation that led to the mobilization of a large Han naval force into Nanyue.