In 209, after the Battle of Red Cliffs, Chen Lan (陳蘭) and Mei Cheng (梅成) started a rebellion in Lu County (六縣; in present-day Lu'an, Anhui). Cao Cao sent two separate forces to suppress the rebellion: Yu Jin and Zang Ba to attack Mei Cheng; Zhang Liao, with Zhang He and Niu Gai (牛蓋) as his deputies, to attack Chen Lan. Mei Cheng pretended to surrender to Yu Jin, and then led his men to join Chen Lan at Mount Tianzhu as soon as Yu Jin and Zang Ba left. The paths leading up the mountain were narrow and dangerous to travel on.