The Grand Commandant (太尉 Tàiwèi) was one of the Three Excellencies and the highest military office in Han government. The holder stood at the top of the military hierarchy and shared in the supreme civil and ceremonial authority of the three ministers.
Role and evolution
In theory the Grand Commandant oversaw military affairs and advised the emperor on war and defence. Over the Eastern Han the post was sometimes left vacant to reduce the power of the military establishment, or filled by a trusted relative or general. By the late Han, powerful regents such as Cao Cao often took the title to legitimise their control of the army and the court.
In the Three Kingdoms period
Cao Cao and other Wei strongmen held or were granted the Grand Commandancy. In Shu and Wu, equivalent or analogous titles were used for the chief military figure. The title remained a symbol of the highest martial authority under the sovereign, even when real power lay with whoever held it.