The Great Schism of the East

The word "schism" in Catholic law

The Code of Canon Law defines schism as the refusal of submission to the Supreme Pontiff or the refusal of communion with the members of the Church subject to him.^[9] The definition is deliberately ecclesiological: it does not say first that a schismatic denies a dogma, but that a visible rupture of communion has occurred within the one ecclesial body. The Catholic Encyclopedia distinguishes in the same sense heresy, which perverts a truth of faith, from schism, which breaks ecclesiastical union.^[10]

This distinction sheds light on 1054. Doctrinal controversies exist, especially on the Filioque and Roman primacy, but the first public act is a rupture of communion between persons and sees: Roman legates, Patriarch of Constantinople, Constantinopolitan synod.^[11] That is why two simplifications must be avoided: saying that the schism is only a political dispute, or saying that it is only a quarrel over theological words.

A schism, not a denial of the whole Christian East

The contemporary Catholic position requires precise language. The Orthodox of Byzantine tradition are not a Christian community born of a modern rupture without apostolic succession; they retain the episcopate, the priesthood, the Eucharist, the veneration of the Fathers, the Byzantine liturgy and a large part of the common dogma of the first millennium.^[12] Vatican II even asks Catholics to know, venerate and preserve the liturgical and spiritual heritage of the East in order to serve the reconciliation of the Christians of East and West.^[13]

"The Churches of the East, like those of the West, have the right and the duty to govern themselves according to their own particular disciplines." — Second Vatican Council, Orientalium Ecclesiarum, no. 5^[14]

The rupture therefore concerns full communion with the successor of Peter, not the existence of an authentic Eastern Christian tradition. The tragedy lies precisely there: two apostolic ecclesial worlds, long united in the same Trinitarian, Eucharistic and conciliar faith, end up living as two separate communions.

Two political centres and two theological languages

Rome and Constantinople do not live in the same institutional world. The Latin West rebuilds itself after the invasions, develops its canon law and looks to the pope as the visible principle of unity. The Byzantine East lives around a continued Roman Empire, a Christian imperial capital and a Patriarchate of Constantinople which became, after Chalcedon, the second see in the order of honour — a rank that canon 28 of the council granted to "New Rome", but which the Roman legates and then Pope Saint Leo I himself refused to recognise.^[15][16]

Ancient bilingualism gradually disappears. Latins read less Greek; Greeks read less Latin. A theological formula can then change scope according to language. The debate on the procession of the Holy Spirit provides the example: the Latin procedere and the Greek ekporeuesthai do not overlap perfectly, which complicates the Eastern reception of the Filioque.^[17]

The Photian crisis as a dress rehearsal

In the 9th century, the crisis of Photius already sets Rome and Constantinople against each other over a contested patriarch, jurisdiction over Bulgaria, the role of the Roman legates and the Eastern denunciation of the Filioque.^[18] This crisis does not yet create the lasting separation: communion is restored, and the article devoted to the Photian Schism shows why this episode must be distinguished from 1054.

But Photius gives the conflict a lasting grammar. The East can accuse the West of altering the Creed; Rome can judge that an Eastern patriarchate cannot constitute itself against the judgment of the Apostolic See; Bulgaria shows that mission also becomes a rivalry of jurisdiction.^[19] In 1054, the names change, but the reflexes are already there.

The Filioque: dogma, formula and insertion into the Creed

The Filioque means that the Holy Spirit proceeds from the Father and the Son. For Catholic doctrine, this is not a matter of positing two competing principles in the Trinity: the Council of Florence will define that the Spirit proceeds from the Father and the Son "as from one single principle and one single spiration" — spiration denoting the eternal act by which the Holy Spirit proceeds.^[20] This precision answers directly the Eastern objection that the West makes the Father and the Son two separate sources of the Spirit.

The dossier nevertheless has two levels. On the one hand, there is the dogmatic truth that the West professes. On the other, there is the Latin insertion of the word into the Nicene-Constantinopolitan Symbol, which the East judges illegitimate without an ecumenical council received by all. Pope Leo III, though favourable to the doctrine of the Filioque, refused its liturgical insertion into the Creed: seized of the decrees of the Council of Aachen of 809, he approved the doctrine conveyed by the Filioque but advised omitting the word from the Symbol — which shows that the controversy cannot be reduced to a simple opposition between orthodoxy and heresy.^[21]

Michael Cerularius closes the Latin case

Michael Cerularius becomes Patriarch of Constantinople in 1043. In 1053, he launches an offensive against Latin usages: the Latin churches of Constantinople are closed, and the Latins are accused in particular of using unleavened bread in the Eucharist.^[22] The quarrel seems liturgical, but it touches a deeper question: the Byzantine East refuses to let Latin usage be presented as the universal norm, while Rome refuses to let Constantinople judge as heretical the legitimate usages of the Latin Church.

The political situation aggravates everything. Emperor Constantine IX Monomachos seeks rather an alliance with the Latins against the Normans; the patriarch, for his part, acts as head of a Byzantine ecclesial bloc. In this context, the Roman mission sent by Leo IX arrives in a capital where the conflict is already laden with humiliation, rivalry and suspicion.^[23]

Leo IX, Humbert and the bull laid at Hagia Sophia

Pope Leo IX had sent legates to Constantinople, led by Cardinal Humbert of Silva Candida. On 16 July 1054, while Leo IX has already been dead since 19 April, Humbert lays on the altar of Hagia Sophia a sentence of excommunication aimed at Michael Cerularius, Leo of Ohrid and their partisans.^[24][25] Historians wonder whether this sentence is valid: the legates acted in the name of a pope already dead, at a time when Rome no longer had a pope.^[26]

This detail matters: the sentence did not target the whole Greek Church as such. The Catholic Encyclopedia stresses that the legates distinguished the emperor, the senate and the majority of the inhabitants of Constantinople, regarded as orthodox, from Cerularius and his circle.^[27] The joint declaration of 1965 will likewise take up this precision: it speaks of a sentence against Michael Cerularius and two other persons, then of a reply against the legates.^[28]

Constantinople's reply

Michael Cerularius does not receive the sentence as a personal correction. The Synod of Constantinople condemns the legates, and the affair rapidly becomes a symbol of rupture between two ecclesial worlds.^[29] In the short term, it is not yet a universal excommunication of all Easterners against all Latins; in the long term, collective memory will turn the incident into the founding date of the schism.

This transformation is decisive. A quarrel of persons could have been healed, like other temporary ruptures. But the Eastern patriarchates, the Slavic Churches and the Byzantine people gradually grow accustomed to living without commemorating the pope in the diptychs — the liturgical lists of bishops named at Mass, from which a name is erased when communion is broken — while the West increasingly thinks of itself as the Roman communion separated from an East rebellious against primacy.^[30]

Roman primacy

The central disagreement is the way in which the pope's primacy is exercised in the universal Church. Catholics confess that the successor of Peter possesses a true primacy of government, not a mere protocolar honour. The Orthodox often recognise in Rome a primacy of honour in the first millennium, but refuse to let this primacy become an immediate and universal jurisdiction over all the local Churches.^[31]

Contemporary Catholic-Orthodox dialogue does not deny primacy; it seeks how to understand it together with synodality. The document of Chieti of 2016 affirms that a "first" exists at different levels of the synodal life of the Church, and that the history of the first millennium is decisive for recovering a common understanding.^[32]

The Filioque

The question of the Filioque becomes the most famous doctrinal argument. For Catholics, Florence fixes the dogmatic meaning: the Father remains the source of all divinity, and the Son holds from the Father that by which the Spirit also proceeds from him.^[33] For the Orthodox, the Latin formula risks obscuring the monarchy of the Father — the Father as the sole source of divinity, from whom the Son is begotten and the Spirit proceeds — and, above all, it was added to the Creed without an Eastern ecumenical reception.

The following table distinguishes the levels often mixed together in polemics.

Rites: unleavened bread, fasts, married clergy

Liturgical usages played a disproportionate role because they made the difference visible. The Latins use unleavened bread in the Eucharist; the Byzantines use leavened bread. The disciplines of fasting, of Saturday, of confirmation and of the married clergy differ too.^[34] In themselves, these differences could have remained legitimate: Vatican II explicitly recognises that the Eastern Churches have the right and the duty to govern themselves according to their particular disciplines.^[35]

The problem arises when a local discipline is turned into an accusation of heresy. Accusing the Latins of Eucharistic invalidity because they use unleavened bread, or accusing the Greeks of infidelity because they maintain a married clergy according to their discipline, amounts to confusing unity of faith with uniformity of rite. The Catholic Church, through its Eastern Catholic Churches, shows precisely that Roman communion can contain several legitimate rites.

1204: the wound of the sack of Constantinople

The schism becomes almost irreparable in Byzantine memory with the sack of Constantinople by the Fourth Crusade in 1204. Latin crusaders, diverted from their initial goal, take and plunder the Christian capital of the East, then install a Latin empire and a competing Latin hierarchy.^[36] Even if this event is not the first cause of 1054, it gives Eastern anti-Latinism massive historical proof: the Latins are no longer merely liturgical adversaries, but occupiers.

Theology never works in a vacuum. A thesis on Roman primacy is received differently when it arrives after a pillage, relics carried off, humiliated churches and Latin political domination. Catholic-Orthodox dialogue must therefore treat doctrines and historical wounds together.

Lyons II and Florence: two fragile unions

Two great councils attempt to restore unity. At the Council of Lyons II in 1274, Emperor Michael VIII Palaiologos accepts a formula of union in order to obtain Western support. At the Council of Florence in 1439, Emperor John VIII Palaiologos, Patriarch Joseph II and the Greek delegates discuss at length with the Latins, then the bull Laetentur Caeli proclaims the union.^[37][38]

"Let the heavens rejoice and let the earth exult." — Eugene IV, Laetentur Caeli, 6 July 1439^[39]

Florence settles on paper the great dossiers: Filioque, unleavened or leavened bread, purgatory, Roman primacy. But the Eastern reception fails. Mark of Ephesus refuses the union, the Byzantine people remain distrustful, Constantinople falls to the Ottomans in 1453, and the union does not take lasting root in the Orthodox Churches.^[40][41]

The Eastern Catholic Churches

Not all Eastern traditions remain outside communion with Rome. Several Eastern Catholic Churches live the Eastern liturgy, discipline and theology in full communion with the Apostolic See. Vatican II asks them to preserve their proper heritage, not to Latinise themselves as if Catholic communion required the erasure of the East.^[42]

This reality matters for reading the Eastern Schism. It shows that the Catholic question is not "East against West" as two incompatible civilisations. The real question is visible communion around Peter, with a legitimate diversity of rites, disciplines and theological traditions.

On 7 December 1965, at the end of Vatican II, Paul VI and Patriarch Athenagoras I have read simultaneously at Rome and Istanbul a joint declaration. The text regrets the offensive words, the unfounded reproaches and the reprehensible gestures that accompanied the events of 1054; it removes from the Church's memory the sentences of excommunication of that time.^[43]

"This gesture of justice and mutual forgiveness, Pope Paul VI and Patriarch Athenagoras I with his synod are aware, cannot suffice to put an end to the differences, ancient or more recent, which subsist between the Roman Catholic Church and the Orthodox Church [...]" — Joint Declaration of Paul VI and Athenagoras, 7 December 1965^[44]

The precision is crucial: 1965 does not restore full Eucharistic communion. The text itself says that differences remain and that they will have to be overcome by purification of hearts, regret for historical wrongs and a common understanding of the apostolic faith.^[45] But 1965 removes the most wounding juridical symbol and opens a new stage of dialogue.

The Great Schism of the East is neither a one-day accident nor a fatality between two foreign Christianities. It is the gradual crystallisation of a rupture between Rome and Constantinople: imperial rivalries, hardening of identities, the Photian crisis, Trinitarian debate, Roman primacy, crossed wounds and failures of conciliar reception.

For a Catholic, the visible unity of the Church presupposes communion with the successor of Peter. For an Orthodox, unity must respect the synodality of the local Churches and the tradition received from the first millennium. The most serious dialogue denies neither of these two poles: it seeks how primacy and synodality can be exercised together, in the apostolic faith and in charity.^[46]

The spiritual conclusion is simpler than the historical dossier: the schism is a sin against the visibility of Christian unity, even when responsibilities are mixed. The Catholic Church does not ask that the facts be forgotten; it asks that they be looked at in truth, so that memory ceases to be a weapon and becomes again a path of conversion.

• Read The Photian Schism to understand the 9th-century precedent.
• Read Answers to Orthodoxy for the current questions of primacy, Filioque and Catholic-Orthodox dialogue.
• Read Constantinople IV for the Catholic council linked to the Photian crisis.
• Retain the main distinction: 1054 is the symbolic date; the real separation is a long historical process.