Chang’an (長安), near modern Xi’an in Shaanxi, lay on the Wei River plain at the western end of the Guanzhong basin. As the capital of the Western Han dynasty it had long symbolised imperial authority, with palaces, markets, and defensive passes guarding the approaches from the east.
During the late Eastern Han, the warlord Dong Zhuo seized control of the central government and moved the court from Luoyang to Chang’an. From there he ruled through violence and intimidation until 192, when a plot led by Wang Yun and Lü Bu lured him into an ambush near the Northern Side Gate of Chang’an and killed him. In the aftermath, Dong Zhuo’s former officers Li Jue, Guo Si, and others fought over the city and the person of Emperor Xian, plunging the capital into chaos.
Although the political centre later shifted east to Xuchang and Luoyang under Cao Cao, Chang’an remained a key stronghold in the Wei River valley and a symbolic reminder of the earlier Han capitals.