Han conquest of Gojoseon  The Han conquest of Gojoseon was a campaign launched by Emperor Wu of Han China against Wiman Joseon between 109 and 108 BCE. It resulted in the fall of Gojoseon and the establishment of the Four Commanderies of Han in the northern half of the Korean Peninsula. Wi Man, or Wei Man (Chinese), was originally a general in the vassal kingdom of Yan under the rule of Lu Wan. In 195 BCE, Lu Wan was implicated in plotting rebellion against the Han dynasty, and Emperor Gaozu of Han sent an army against him. Yan was defeated, and Lu Wan fled to the Xiongnu, while Wi Man sought refuge in the eastern kingdom of Gojoseon. Wi Man and one thousand of his followers adopted the dress of the Koreans and little by little, he gained a large following of both native Koreans and Chinese refugees. He then usurped the throne of King Jun of Gojoseon, who fled south to Jin. The governor of Liaodong agreed to acknowledge Wi Man as a foreign vassal of Han so long as he guarded their border against barbarian intrusions, and to allow passage any barbarians who wished to pay their respects to the Han emperor. Wi Man's grandson, King Ugeo of Gojoseon, interrupted direct contact with envoys sent by chiefs of various tribes on the Korean Peninsula to the Han court. In 109 BCE, Emperor Wu of Han dispatched She He (涉何) to rebuke King Ugeo. After an audience with the king, She He failed in securing safe passage for the envoys. On the return trip, She He killed Wi Jang (長降), an assistant who had been sent to escort him home. This angered King Ugeo, who sent troops into Han territory to kill She He. The direct pretext for war thus came when King Ugeo had the Han envoy executed, which angered Emperor Wu considerably. The initiation of war may also have been brought by the desire to remove the possibility that Gojoseon would ally with the Xiongnu against the Han. Another reason may also have been the deteriorating relations between Han and Gojoseon, because Wiman Joseon had prevented trade between Han and polities such as Jinbeon (진번, 眞番). In 109 BCE, Emperor Wu launched a Han military campaign into Gojoseon. Yang Pu (楊僕) and Xun Zhi (荀彘) respectively—set out from the Han empire to invade Gojoseon.