She was a minister at the Vulcan monastery on P'Jem sometime before becoming a leader of a rebel cell on planet Vulcan. As such, T'Pau ordered the death of T'Les, a pacifist member of the rebellion and the mother of T'Pol.
In 2155, T'Pol delivered schematics from the USS Defiant to T'Pau, as well as the knowledge that the Defiant was from a parallel universe, news which convinced the rebel leader theirs was not a lost cause. T'Pau brought together fellow rebels Gral and Navaar, who united forces to capture Empress Sato and put her on public trial.
T'Pau gave T'Pol command of the starship Ni'Var, but eventually came to question her loyalties, and ordered fellow rebel Staal to murder her. T'Pol survived the attempt on her life, and instead killed T'Pau in the caverns underneath Aldus Prime. (ENT - Mirror Universe novel: Age of the Empress)