赫连勃勃
Li Yichao refused to follow Li Siyuan's orders. Rather, he sent his older brother or cousin (only known historically by the nickname of Prince Aluo () to defend against the Later Tang attack at Qingling Gate (青嶺門, in modern Yan'an), and also gathered up all Dangxiang tribesmen in his territory for the defense. The Later Tang forces under Yao and An put Xia Prefecture under siege. However, the city walls were said to be exceedingly firm based on original construction by Helian Bobo, and the Dangxiang tribesmen were able to effectively cut off food supply routes of the Later Tang army such that it was difficult to resupply the army. Li Yichao and his brothers went on the city walls and begged An to withdraw, stating to him: