Mount Dingjun
In 215 Cao Cao eliminated Zhang Lu and occupied Hanzhong Commandery. Cao Cao attacked Sun Quan again in 217 after Sun Quan's failed attack in 215. However he was never able to make it past the Changjiang defenses but was able to gain Sun Quan's nominal surrender. In the spring of 219, his general Xiahou Yuan was killed at the Battle of Mount Dingjun and Cao Cao lost his position in Hanzhong Commandery. Liu Bei's general Guan Yu also defeated Yu Jin's fores in Nanyang Commandery and laid siege to Cao Ren in Fancheng. However he was unable to take the city and was himself killed when Sun Quan's general Lü Meng who took advantage of the situation and attacked him from behind. Cao Cao died soon afterward on 15 March, 220. He was succeeded by his son Cao Pi.