In the summer of 99 BC, Li Guangli and three other Han generals led a force of 35,000 against the Xiongnu in the Tian Shan range. Initially successful, Li Guangli defeated the Wise King (Tuqi) of the Right and killed some 10,000 Xiongnu, but was surrounded on the way back and had to defend himself. They managed to drive back the Xiongnu before trying to head back to China. The Xiongnu gave chase leading to heavy casualties for the Han army. Li Guangli only returned with less than half of his original army. The other Han generals, Li Ling and Lu Bode, had been left further back earlier as a rear guard, but Lu Bode objected to serving under Li Ling and decided to advance with only 5,000 infantry, confident that his force of crossbowmen would be able to handle any Xiongnu force they encountered. He was confronted by a force of 30,000 Xiongnu and had set up fortifications between two hills. The Xiongnu made repeated charges on his position, but failed to overcome Li Ling's crossbow and shield/spear formation, suffering heavy casualties. When Li Ling's forces sought to retreat, but the Xiongnu chased after them, harassing them until nightfall. Only 400 men made it back and Li Ling was captured.