It was fought Hostile_encounter in the winter of AD 208/9 between the allied forces of the southern warlords Sun Quan and Liu Bei and the numerically superior forces of the northern warlord Cao Cao .

Liu Bei and Sun Quan successfully frustrated Preventing_or_letting Cao Cao 's effort to conquer Conquering the land south of the Yangtze River and reunite Cause_to_amalgamate the territory of the Eastern Han dynasty .

The allied victory at Red Cliffs ensured Preventing_or_letting the survival Preserving of Liu Bei and Sun Quan , gave Giving them control of the Yangtze , and provided Supply a line of defence that was the basis for the later creation Creating of the two southern states of Shu Han and Eastern Wu .