Battle of Guandu
The Battle of Guandu was fought between the warlords Cao Cao and Yuan Shao in 200 AD in the late Eastern Han dynasty. Cao Cao's decisive victory against Yuan Shao's numerically superior forces marked the turning point in their war. The victory was also the point at which Cao Cao became the dominant power in northern China, leading to the establishment of the state of Cao Wei in the Three Kingdoms period.