Title: Poslanieto na t︠s︡arigradskii︠a︡ patriarkh Fotiĭ do bŭlgarskii︠a︡ kni︠a︡z Boris
Subjects: Schism, Eastern and Western Church, Bŭlgarska pravoslavna t︠s︡ŭrkva, Catholic Church
Places: Bulgaria
People: Boris I Khan of Bulgaria (-907), Photius I Saint, Patriarch of Constantinople (approximately 820-approximately 891)