Battle of Chang Ban
The battle of Chang Ban
was when Cao Cao, founder of the Wei Dynasty, was pursuing Liu Bei, founder of the Shu dynasty. Zhang Fei and Guan Yu helped defend Liu Bei until Zhuge Liang and Mei Senniang came as reinforcements. Liu Bei was trying to get to Xia Kou in north Wu.
In the middle of battle Zhang Fei did a famous yell at 10,000 of Yu Jin's troops and scared them all off. Cao Cao led the pursuit to catch Liu Bei but failed to catch him. This led to the battle of Chi Bi, with the alliance pledged with Sun Quan, ruler of Wu.