Hanzhong Campaign
At that time, Liu Bei was besieging Liu Zhang in Yi Province's capital Chengdu, when he received Ma Chao's request to serve him. Liu Bei was pleased and eagerly accepted Ma Chao's assistance, and sent troops and supplies to Ma Chao's camp. Following that, Ma Chao led his army to attack Chengdu from the north. Liu Zhang was shocked because he did not expect Ma Chao to make such a move. Shortly later, Liu Bei's adviser Jian Yong managed to convince Liu Zhang to surrender, and Yi Province came under Liu Bei's control. Ma Chao became one of the Five Tiger Generals under Liu Bei after the latter defeated Cao Cao in the Hanzhong Campaign and declared himself "King of Hanzhong".