The Battle of Red Cliffs, also known as the Battle of Chibi, was a decisive naval battle in the winter of AD 208–209 at the end of the Han dynasty, about twelve years prior to the beginning of the Three Kingdoms period in Chinese history.[4] The battle was fought between the allied forces of the southern warlords Sun Quan, Liu Bei, and Liu Qi against the numerically superior forces of the northern warlord Cao Cao. Liu Bei and Sun Quan frustrated Cao Cao's effort to conquer the land south of the Yangtze River and reunite the territory of the Eastern Han dynasty.