Question 62 · The Church

Why did the Eastern and Western churches separate?

What the sources show

Firmilian of Caesarea c. 256 · Council of Constantinople (as Socrates reports) c. 381Papal authority

There was no single break. Tensions over Rome's authority go back to the third century, and the East ranked sees by the imperial capital, "New Rome". ¹²

Council of Florence 1439 · Russian Orthodox Church (Moscow Patriarchate) 2013 · Photius of Constantinople c. 867 · Humbert of Silva Candida 1054 · Niketas Choniates 1206

The open quarrels came over the filioque added to the Western creed (see question 16) and over papal claims: Photius in 867, the mutual excommunications of 1054, the sack of Constantinople in 1204. Florence (1439) tried to reunite them on Rome's terms and failed. ³⁴⁵⁶⁸

Paul VI and Athenagoras I 1965Papal authority

In 1965 Paul VI and Athenagoras I together lifted the anathemas of 1054 and committed them to oblivion, though the division itself remained. ⁷

The answers given:

ApostolicBefore NicaeaNicaea and afterMiddle AgesReformation to today

Scroll through the centuries, or tap a dot. J K move between witnesses.

Before Nicaea

150–325

256c. AD

Papal authority

Firmilian of Caesarea d. c. 269 ADLetter 75, to Cyprian 75.17

I am rightly angry at this open and plain folly of Stephen: he who boasts so of the place of his episcopate and claims to hold the succession of Peter, on whom the foundations of the Church were laid, brings in many other rocks and sets up new buildings of many churches.

Already in 256 an Eastern bishop rejected Rome's claim to settle a dispute for all churches.

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Nicaea to Chalcedon

325–451

381c. AD

Papal authority

Council of Constantinople (as Socrates reports)Socrates, Church History 5.8

Then they also issued a decree that the bishop of Constantinople should have the privileges of honor after the bishop of Rome, because it is New Rome.

Ranking sees by the imperial capital, rather than by apostolic founding, set East and West on different paths. Rome rejected the canon, and the later canon 28 of Chalcedon.

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Late antiquity and Byzantium

451–1054

867c. AD

The filioque

Photius of Constantinople c. 810–c. 893 ADEncyclical Letter to the Eastern Patriarchs 2

They tried to falsify the holy Creed ... by coining the new teaching that the Holy Spirit proceeds not from the Father only, but also from the Son

The first Eastern charge sheet against Rome, sent to the other patriarchs in 867. The filioque heads the list of Latin errors: Photius is charging the Frankish missionaries in Bulgaria with falsifying the Creed itself.

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Middle Ages

1054–1500

1054AD

Papal authority

Humbert of Silva CandidaBull of Excommunication 1054

Michael, a usurping patriarch, a neophyte ... and all their followers in the errors and presumptions named above: let them be anathema Maranatha ... with the devil and his angels

Laid on the altar of Hagia Sophia on 16 July 1054. Cerularius and his synod answered with their own anathemas days later; the mutual sentences were lifted only in 1965.

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1206AD

Papal authority

Niketas ChoniatesHistory on the sack of 1204

Mules and pack animals, laden, were led in as far as the sanctuary of the church ... a wretched little woman, heaped with sins ... let out a loose and broken song

A Byzantine official who lived through the sack of April 1204; his account is a chief reason 1204, more than 1054, fixed the separation in Greek memory. In the full passage the woman is seated on the patriarchal throne in Hagia Sophia. The 1835 scan is rough and some words are hard to read in it; the words quoted follow the standard printed text.

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1439AD

Papal authority

Council of FlorenceLaetentur Caeli Decree of union

to him was committed in blessed Peter the full power of tending, ruling and governing the whole church

The reunion decree, signed by the Byzantine emperor and most Greek bishops, accepted the filioque and Roman primacy. It was rejected in Constantinople and never took hold.

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Modern churches

1700–today

1965AD

Papal authority

Paul VI and Athenagoras IJoint Catholic-Orthodox Declaration 4.B

They likewise regret and remove both from memory and from the midst of the Church the sentences of excommunication which followed these events ... and they commit these excommunications to oblivion.

Read simultaneously in Rome and Istanbul on 7 December 1965, at the close of the Second Vatican Council. It lifted the mutual sentences of 1054, but it did not restore communion: the declaration itself says this gesture was not sufficient to end the old and more recent differences between the two churches (para. 5). Copy saved as outputs/question-dossiers/witnesses/url-paul-vi-athenagoras-1965-declaration.txt.

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2013AD

Papal authority

Russian Orthodox Church (Moscow Patriarchate)Position on the problem of primacy in the Universal Church §2

They also believed that primacy in honour accorded to the bishops of Rome is instituted not by God but men.

The Orthodox position on the root of the split.

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How this page was made

Every early quote was read in its Greek or Latin and translated for this page by Claude (Opus 5.5) on 13 October 2026. Each line names the printed edition it was read from. A quote marked indirect does not state the answer outright; read its note. A writer's silence is never counted as an answer.