沮渠蒙遜
In 420, Juqu Mengxun set another trap for Li Xin. He pretended to attack Western Qin's city Haomen (浩亹, in modern Haidong Prefecture, Qinghai), but once reaching Haomen, immediately withdrew and hid his army at Chuanyan (川巖, near Zhangye). Li Xin, believing wrongly that Juqu Mengxun's defenses were down, decided to attack Zhangye, against the advice of Song Yao and Zhang Tishun, as well as his mother Princess Dowager Yin. As he approached Zhangye, Juqu Mengxun intercepted him and defeated him. His generals then advised him to quickly withdraw to Jiuquan, but Li Xin, stating that he had disobeyed his mother and would only be able to see her again after a victory, engaged Juqu Mengxun again, suffering an even greater defeat, and he was killed in battle. Juqu Mengxun quickly captured Jiuquan and most of Western Liang territory. He largely maintained a policy of trying to pacify the Western Liang people and incorporating capable Western Liang officials into his administration, including Li Gao's half-brother Song Yao (宋繇). In winter 420, Li Xin's brother Li Xun seized Dunhuang and tried to reestablish Western Liang rule, and Juqu Mengxun initially sent Juqu Zhengde to siege Dunhuang. In spring 421, he attacked Dunhuang himself, and when Li Xun tried to surrender, he refused. Li Xun's official Song Cheng (宋承) rebelled and offered the city to him, and Li Xun committed suicide, ending Western Liang; contrary to the pacification policy he carried out at Jiuquan, Juqu Mengxun slaughtered the populace of Dunhuang.