Controversy between Eastern and Western Christianity in the 9th century, triggered by the opposition of the Roman pope to the appointment of Photius as patriarch of Constantinople.
Ecclesiastical rights of jurisdiction in the Bulgarian church and a doctrinal dispute over the insertion of the Filioque ("and from the Son") clause in the Nicene Creed were also at issue. Photius withdrew from communion with Rome in 867; he himself was finally exiled in 886.