In the mirror universe, Petri was a Troyian ambassador. In 2268, he was responsible for educating Elaan in Troyian customs, but was stabbed and wounded for his troubles. The assault imperiled the success of the mission, after Petri refused to deal with Elaan any further. The only person to whom the Dohlman would consent to receive further instruction in etiquette was the highest-ranking individual on the ship: Captain Spock. (TOS - Mirror Universe novel: The Sorrows of Empire)