 In 755, An Lushan rebelled against Emperor Xuanzong's rule, and soon captured the Tang eastern capital Luoyang and declared himself emperor of a new state of Yan.The military governor of Pinglu, Lü Zhihui (), was a follower of An's, and he trapped and killed the deputy Protectorate General to Pacify the East, Fumeng Lincha ().In response, Dong Qin and his colleagues Liu Kenu () and Wang Xuanzhi () killed Lü and took over the circuit, remaining in remote contact with Yan Zhenqing, one of the few Tang generals resisting Yan forces north of the Yellow River.