Michael I Cerularius

Lore & Background

Michael I Cerularius became Ecumenical Patriarch of Constantinople. In 1053, he ordered the closure of all Latin churches in Constantinople, the first action that led to a formal schism. In 1054, the papal legate sent by Leo IX traveled to Constantinople 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, and 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, attacks that had the support of Cerularius. When the leader of the legation, Cardinal Humbert of Silva Candida, learned that Cerularius had refused to accept the demand, he excommunicated him, and in response Cerularius excommunicated Humbert and the other legates. The validity of the Western legates' act is doubtful because Pope Leo had died and Cerularius' excommunication only applied to the legates personally. Still, the Church split along doctrinal, theological, linguistic, political, and geographical lines, and the fundamental breach has never been healed.

Reader's Guide

Michael I Cerularius is a pivotal figure in the history of Christianity, as his conflicts with Pope Leo IX directly contributed to the Great Schism of 1054, which permanently divided the Eastern Orthodox and Roman Catholic churches. The schism was not solely his doing, but his refusal to accept papal supremacy and his insistence on Greek practices—such as leavened bread—crystallized long-standing tensions. The excommunications exchanged in 1054 were later nullified in 1965 by Pope Paul VI and Ecumenical Patriarch Athenagoras I, though this was merely a gesture of goodwill and did not constitute a 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, when those members spontaneously request these. 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.

Did You Know?

• In 1053, Michael I Cerularius ordered the closure of all Latin churches in Constantinople, the first action that led to a formal schism.
• Cardinal Humbert excommunicated Cerularius in 1054, but the validity of the act is doubtful because Pope Leo had died.
• Cerularius' excommunication only applied to the legates personally, not to the entire Western Church.
• In 1965, Pope Paul VI and Ecumenical Patriarch Athenagoras I nullified the anathemas of 1054, though this did not constitute a reunion.
• Every year a delegation from each church 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.