An Qingxu
In spring 757, An Lushan was killed by his son An Qingxu, who succeeded to the Yan throne. Meanwhile, though, Shi Siming, who had not received the news of An Lushan's death, attacked Taiyuan, where Li Guangbi was at that point, along with Cai Xide, Gao Xiuyan (), and Niu Tingjie (), with 100,000 troops total. They besieged Taiyuan for more than a month, but could not capture it. The news of An Lushan's death then arrived, and An Qingxu further ordered Shi to return to Fanyang to guard it, leaving Cai at Taiyuan to watch Li Guangbi. An Qingxu also made Shi the military governor of Fanyang and created him the Prince of Guichuan. Shi, however, hoarding the supplies that An Lushan had previously shipped to Fanyang, began to disobey An Qingxu's orders, and An Qingxu could not keep him in check. In winter 757, after An Qingxu was forced to abandon Luoyang after a joint Tang/Huihe counterattack, various non-Han tribal troops abandoned An Qingxu and fled north. Shi induced the elite Yeluohe () troops, as well as various other tribes, to submit to him, but the Tongluo () forces refused, and he then defeated them.