As the Han Dynasty central government's power collapsed, the warlords Gongsun Zan and Yuan Shao fought for control of northern China. After years of destructive war, Gongsun Zan grew weary. He built a splendid fortification at Yi (易), located on the northern bank of Yi river, called it Yijing (易京, meaning "Capital Yi"). He stored enough provisions to last tens of years, locking himself inside, intended to wait for "peace".
Taking the initiation, Yuan Shao went for the kill. Having amassed a massive army, he easily cut through Gongsun Zan's border defense fortifications because Gongsun Zan refused to relieve them. Before long, Yuan Shao and his huge army appeared in front of Yijing.
Alarmed, Gongsun Zan sent his son, Gongsun Xu to ask for help from the leaders of the Heishan bandits.
In the spring of 199, Zhang Yan, leader of the Heishan bandits, joined with Gongsun Xu to lead the relieving force advancing in 3 columns. Before they arrived, Gongsun Zan lost the Battle of Yijing and died.
Gongsun Xu was killed by the Xiongnu group Chuge (屠各).
- Book of Later Han, Vol. 79 "Biographies of Liu Yu, Gongsun Zan, and Tao Qian"
- de Crespigny, Rafe. "To Establish Peace: being the Chronicle of the Later Han dynasty for the years 189 to 220 AD as recorded in Chapters 59 to 69 of the Zizhi tongjian of Sima Guang". Volume 1. Faculty of Asian Studies, The Australian National University, Canberra. 1996. ISBN 0-7315-2526-4.