Qifu Gangui
The first actual historical reference to Lü Zuan was in 392, when he served as one of his father Lü Guang's generals in his campaign against Qifu Gangui, the prince of Western Qin, and Lü Zuan was unsuccessful in his attack on Qifu Gangui. In 397, Lü Guang, who had by then claimed imperial title, sent his son Lü Zuan (then referred to as the Duke of Taiyuan) and his brother Lü Yan (呂延) against Qifu Gangui, who had previously agreed to be a vassal and then changed his mind. Initially, Lü Zuan was successful, capturing the important city Jincheng (金城, in modern Lanzhou, Gansu), but after his uncle was defeated and killed in a trap laid by Qifu Gangui, Lü Zuan was forced to withdraw.