Li Guang

Li Guang committed suicide shortly after the Battle of Mobei in 119 BC. He was blamed for failing to arrive at the battlefield in time (after getting lost in the desert), creating a gap in the encirclement and allowing Ichise Chanyu to escape after a confrontation between Wei Qing and the Chanyu's main force, which the Han army narrowly managed to defeat. Refusing to accept the humiliation of a court-martial, Li Guang killed himself.
Li Guang belonged to the Longxi branch of the Li clan (隴西李氏). Li Guang was a descendant of Laozi and the Qin general Li Xin, as well as an ancestor of the Western Liang and Tang dynasty monarchs. Li Guang was the grandfather of general Li Ling who defected to the Xiongnu. Provided by Wikipedia