Gojoseon–Han War

The Gojoseon–Han War was a campaign launched by the Han empire against Wiman Joseon of the Gojoseon kingdom between 109 and 108 BC. It resulted in the fall of Gojoseon.

Background
Since the time that Wiman took the Gojoseon throne, relations between Han and Gojoseon had been deteriorating. King Ugeo of Gojoseon interrupted direct contact with envoys sent by chiefs of various tribes on the Korean Peninsula to the Han empire, thus Emperor Wu of Han dispatched the emissary She He (涉何) to Gojoseon. After an audience with the king, She He failed in securing the safe passage of the envoys. While returning to his nation, She He killed Jang (長), an assistant of the Gojoseon king. Due to this action, the king sent out troops to kill She He. The direct pretext for war thus came when King Ugeo had the Han envoy executed, which had angered Emperor Wu considerably. However, it is thought by modern historians that the initiation of war was also brought by the desire to remove the possibility that Gojoseon would ally with the Xiongnu against the Han or by the deteriorating relations between Han and Gojoseon when Wiman Joseon prevented trade between Chinbon and Han.

Course of the war
In 109 BC, Emperor Wu launched a Han military campaign into Gojoseon. Two forces—totaling about 50,000 troops led by Yang Fu (楊僕) and Xun Zhi (荀彘) respectively—set out from the Han empire to invade the kingdom. A navy sailed from Qi (present-day Shandong Province) across the Bohai Sea towards Gojoseon, while an army marched through Liaodong and headed towards Wanggeom, the capital of Gojoseon.

In a series of unsuccessful attempts by the Han forces to take the city in the first year of the war, King Ugeo kept Wanggeom from the Han forces. Xun Zhi, having overall command by the Emperor Wu, imprisoned Yang Fu and unified the whole Han forces and the attacks became stronger. Wiman Joseon officials such as No In (朝鮮相 路人), Han Eum (相 韓陰), Sam (尼谿相 參), Wang Gyeop (王唊) insisted to surrender to Han. But King Ugeo disagreed. Eventually, in April of 108 BC, three of the ministers surrendered to Han and Sam later let King Ugeo be assassinated. Under the leadership of Minister Seong Gi (成己), Gojoseon people still struggled against Han. But, Seong Gi was also assassinated and the city finally fell to Han.

Aftermath
After the war, four Han commanderies were founded to administer the former Gojoseon territories, namely Lelang, Xuantu, Zhenfan, and Lintun. The most significant commandery was located in Lelang (near present-day Pyongyang), which controlled the region until 313 AD. The conquest of Gojoseon in 108 BC by Han, ultimately led to the Proto-Three Kingdoms period of Korea.