In the summer of 99 BC, Li Guangli and three other generals led a force of 35,000 against the Xiongnu in the Tian Shan range. Initially successful, Li Guangli killed some 10,000 Xiongnu, but was surrounded and had to fortify. They sortied out and managed to drive back the Xiongnu before making a run for it. The Xiongnu gave chase and dealt heavy casualties on the Han army. Li Guangli only returned with 40% of his forces. 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 left. Li Ling decided to advance by himself with only 5,000 infantry, confident that his force of crossbowmen would be able to handle any force they encountered. He was confronted with a force of 30,000 Xiongnu and had to fortify behind a wagon laager 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 made a break for it, the Xiongnu chased after them, harassing them until nightfall. Only 400 men made it back and Li Ling was himself captured.