Emperor Basil, seeking to confirm his deposition of Photios, patriarch of Constantinople, convenes the Fourth Council of Constantinople in 869-870, which issues no new dogmatic decisions and whose principal action is to restore Ignatius by deposing Photi0s for usurping his ecclesiastical position.

Bulgaria is formally placed under the nominal ecclesiastical jurisdiction of the patriarch of Constantinople but receives an independent archbishopric.

This has significant results both for the Balkan principalities and for the Orthodox Church, as well as greatly strengthening imperial Greek influence in the south Slav world.

The council greatly contributes to the growing rift between the Eastern and Western churches.

(The Roman church will eventually recognize it as the eighth ecumenical council, but the Eastern church for the most part will deny its ecumenicity and continue to recognize only the first seven ecumenical councils.)