East–West Schism

The first action that would lead to a formal schism was taken in 1053: the Greek churches in southern Italy were required to conform to Latin practices, under threat of closure.^[8][9][10] In retaliation, Patriarch Michael I Cerularius of Constantinople ordered the closure of all Latin churches in Constantinople. In 1054, the papal legate sent by Leo IX travelled to Constantinople in order, among other things, to deny Cerularius the title of "ecumenical patriarch" and insist that he recognize the pope's claim to be the head of all of the churches.^[1] The main purposes of the papal legation were to seek help from the Byzantine emperor, Constantine IX Monomachos, in view of the Norman conquest of southern Italy, and to respond to Leo of Ohrid's attacks on the use of unleavened bread and other Western customs,^[11] attacks that had the support of Cerularius. The historian Axel Bayer says that the legation was sent in response to two letters, one from the emperor seeking help to organize a joint military campaign by the eastern and western empires against the Normans, and the other from Cerularius.^[12] When the leader of the legation, Cardinal Humbert of Silva Candida, O.S.B., learned that Cerularius had refused to accept the demand, he excommunicated him, and in response Cerularius excommunicated Humbert and the other legates.^[1] According to Ware, "Even after 1054 friendly relations between East and West continued. The two parts of Christendom were not yet conscious of a great gulf of separation between them. ... The dispute remained something of which ordinary Christians in East and West were largely unaware".^[13]


The validity of the Western legates' act is doubtful because Pope Leo had died and Cerularius' excommunication only applied to the legates personally.^[1] Still, the Church split along doctrinal, theological, linguistic, political, and geographical lines, and the fundamental breach has never been healed: each side occasionally accuses the other of committing heresy and of having initiated the schism. Reconciliation was made more difficult by the Latin-led Crusades, the Massacre of the Latins in 1182, the West's retaliation via the Sacking of Thessalonica in 1185, the capture and pillaging of Constantinople during the Fourth Crusade in 1204, and the imposition of Latin patriarchs.^[1] Over time, the emergence of competing Greek and Latin hierarchies in the Crusader states, especially with two claimants to the patriarchal sees of Antioch, Constantinople, and Jerusalem, made the existence of a schism clear.^[14] Several attempts at reconciliation did not bear fruit.


In 1965, Pope Paul VI and Ecumenical Patriarch Athenagoras I nullified the anathemas of 1054,^[1] although this was a nullification of measures taken against only a few individuals, merely as a gesture of goodwill and not constituting any sort of reunion. The absence of full communion between the Churches is even explicitly mentioned when the Code of Canon Law gives Catholic ministers permission to administer the sacraments of penance, the Eucharist, and the anointing of the sick to members of eastern churches such as the Eastern Orthodox Church (as well as the Oriental Orthodox churches and the Church of the East) and members of western churches such as the Old Catholic Church, when those members spontaneously request these.^[15] Contacts between the two sides continue. Every year a delegation from each joins in the other's celebration of its patronal feast, Saints Peter and Paul (29 June) for Rome and Saint Andrew (30 November) for Constantinople, and there have been several visits by the head of each to the other. The efforts of the ecumenical patriarchs towards reconciliation with the Catholic Church have often been the target of sharp criticism from some fellow Orthodox.^[16]