In an alternate timeline, the Vulcan Protectorate was an interstellar state controlled by the Vulcans. In this reality Humans died out in the 1950s (see Miri's World), hence there was no Jonathan Archer to help the Vulcans rediscover the Kir'Shara. (TOS episode & novelization: Miri; ENT episode & novelization: Awakening); (DTI novel: Forgotten History)
In the 22nd century, the militaristic administrator of the Vulcan High Command, V'Las, collaborated with the Romulans to instigate war with the Andorians. After Ambassador Soval's assassination on Paan Mokar the peace talks with the Andorians failed. The Vulcan Muroc subsequently led a guerilla war against them and drove the occupiers off. He was appointed fleet commander in the invasion of Andor. Andor was conquered and a puppet government installed.
At the same time, the Vulcans infiltrated the Romulans and assimilated them into their society.
The Vulcan Protectorate was a rival of the Klingon-Andorian Compact, an alliance formed to counter Vulcan influence in local space. Technologically, both states were behind the Federation due to the lack of multispecies cooperation.