The Battle of Red Cliffs, also known as the Battle of Chibi, was a decisive naval battle in China that took place during the winter of 208–209 AD. It was fought on the Yangtze River between the forces of warlords controlling different parts of the country during the end of the Han dynasty. The allied forces of Sun Quan, Liu Bei, and Liu Qi based south of the Yangtze defeated the numerically superior forces of the northern warlord Cao Cao. By doing so, Liu Bei and Sun Quan prevented Cao Cao from conquering any lands south of the Yangtze, frustrating Cao Cao's efforts to reunify the territories formerly held by the Eastern Han dynasty.