The Battle of Red Cliffs, otherwise known as the Battle of Chibi, was a decisive battle fought at the end of the Han dynasty, about 12 years prior to the beginning of the Three Kingdoms period in Chinese history. It was fought in the winter of 208/9 CE between the allied forces of the southern warlords Liu Bei and Sun Quan and the numerically superior forces of the northern warlord Cao Cao. Liu Bei and Sun Quan successfully frustrated Cao Cao's effort to conquer the land south of the Yangtze River and reunite the territory of the Eastern Han dynasty.