The Ashen Knight: A Sourcebook for Vampire, The Dark Ages

Dark Ages: Vampire takes you to the nights before the Camarilla, when kine truly had reason to be afraid of the dark. The vampires of this bygone age ride the dark as lords, play their games with the crowned heads of Europe, and travel to the mysterious lands of the East as they wage their ages-old war.
The diablerie of saulot, the waking of Mithras, the destruction of Michael the patriarch, the return of the Dracon -- it all means the time of reflection is over. The Inquisition stirs and the time to act is now. Across Europe, monarchs of the night set princes and barons at each other's undying throats. Young vampires take to the field ready to claim their domain and become powerful lords in their own right. Blood calls to blood.

Rules for playing vampire knights.