In the 9th century, a controversy arose between Eastern (Byzantine, Greek Orthodox) and Western (Latin, Roman Catholic) Christianity that was precipitated by the opposition of the Roman Pope John VII to the appointment by the Byzantine Emperor Michael III of Photios I to the position of patriarch of Constantinople. Photios was refused an apology by the pope for previous points of dispute between the East and West. Photios refused to accept the supremacy of the pope in Eastern matters or accept the Filioque clause. The Latin delegation at the council of his consecration pressed him to accept the clause in order to secure their support. The controversy also involved Eastern and Western ecclesiastical jurisdictional rights in the Bulgarian church. Photios did provide concession on the issue of jurisdictional rights concerning Bulgaria, and the papal legates made do with his return of Bulgaria to Rome. This concession, however, was purely nominal, as Bulgaria's return to the Byzantine rite in 870 had already secured for it an autocephalous church. Without the consent of Boris I of Bulgaria, the papacy was unable to enforce any of its claims.