The Filioque Controversy Explained

1. What the Filioque Is

The Filioque is a single Latin word meaning "and the Son", inserted in the Latin West into the clause of the Nicene Creed that confesses the Holy Spirit as the one "who proceeds from the Father". With the addition, Western Christians profess that the Spirit proceeds from the Father and the Son. Eastern Orthodox Christians profess the clause as the Council of Constantinople left it in 381, from the Father alone, and they have objected to the Western wording for more than eleven centuries.

The Latin breaks down simply. Filio is the ablative of filius, son, and the enclitic -que means "and", attached to the end of the word it joins. So ex Patre Filioque procedit reads "proceeds from the Father and the Son". English-speaking Catholics say it every Sunday without noticing, since the Creed at Mass runs "who proceeds from the Father and the Son, who with the Father and the Son is adored and glorified".

Two things make the dispute hard to summarize honestly. The first is that the argument runs on two tracks at once, one about the doctrine of God and one about church authority, and each side has sometimes pressed whichever track was going better. The second is that the key verb does not mean the same thing in Greek and in Latin, so for centuries the two Churches were partly arguing about a translation problem while believing they were arguing about the Trinity. Both tracks are set out below in turn, in the terms the people holding them would use.

2. The Creed Before and After the Addition

The text at issue is one line of the Nicene-Constantinopolitan Creed, the creed recited at the Eucharist in almost every apostolic Church. The Council of Nicaea in 325 said little about the Holy Spirit, ending its creed with the bare words "and in the Holy Spirit". The First Council of Constantinople in 381 filled that out against those who denied the Spirit's divinity, and the expanded clause is what both traditions have recited ever since, with or without three added Latin syllables.

The Two Texts Side by Side

Wordings above follow the standard English liturgical renderings of the Greek text of 381 and of the Latin text as used in the Roman Rite. Translations differ in small details between jurisdictions and language groups. Note that the phrase "with the Father and the Son is worshipped and glorified" is in the original Greek and is not part of the dispute.

Notice how small the change is on the page and how large it is in doctrine. The Creed already confesses that the Spirit is worshipped together with the Father and the Son, so nothing about the Spirit's full divinity is at stake. What the addition touches is the question of origin, of where within God the Spirit comes from, and origin is the only thing that distinguishes the three persons from one another in classical Trinitarian theology. That is why a phrase this short could carry this much weight.

3. How the Words Got Into the Western Creed

The Filioque entered Western use gradually, locally, and for reasons that had nothing to do with the East. The earliest well-attested appearance of the phrase in a creed is in Visigothic Spain, associated with the Third Council of Toledo in 589, at which King Reccared and the Visigothic nobility renounced Arianism and embraced Nicene Christianity. Arianism made the Son less than the Father, so Spanish bishops were looking for language that bound the Son as tightly as possible to the Father's own divine work. Saying that the Spirit proceeds from the Father and the Son did exactly that, since only God can be the source of God.

From Spain the wording travelled into Gaul and then into the churches of the Frankish kingdom, where Charlemagne's court theologians took it up with enthusiasm in the late eighth and early ninth centuries. Frankish writers used it in polemic against Byzantine theology, and Frankish monks in Jerusalem singing the Creed with the Filioque in 808 caused a public quarrel with Greek monks there, which is how the matter reached Rome as a practical problem.

Rome Held Out for Two Centuries

The response of the papacy at this point is one of the most useful facts in the whole history, and Catholics who want to argue the case well should know it. A Frankish council at Aachen in 809 approved the Filioque and asked Pope Leo III to endorse its insertion into the Creed. Leo accepted the doctrine as true, and he refused to put the words into the Creed. According to the account preserved in the papal records, he had the Creed inscribed in both Greek and Latin, without the Filioque, on silver shields set up at St Peter's, as a public witness to the conciliar text.

Rome held that position for roughly two more centuries. The Creed came to be sung at Mass in Rome only in the eleventh century, and it was in that period, commonly dated to 1014 at the imperial coronation of Henry II, that the Roman liturgy took up the Creed with the Filioque already attached from Frankish usage. The Catechism of the Catholic Church treats the history and the doctrine together in paragraphs 246 to 248, noting that the Latin tradition confessed the doctrine long before the formula entered the liturgy at Rome.

4. What "Procession" Means in Greek and in Latin

The fact that does most to clarify the Filioque dispute is that the Greek and Latin words translated "proceeds" do not cover the same ground. The Creed of 381 uses the Greek participle from ekporeuesthai, and the Latin translates it with procedere. The Greek verb is narrow and the Latin verb is broad, and once that is seen, a large part of the quarrel changes shape.

The Greek Verb

In the Greek theological vocabulary settled by the Cappadocian Fathers, ekporeusis names origination from the ultimate source, from the one who has no origin. To say that the Spirit ekporeuetai from the Father is to say that the Father is the sole fountainhead of the Spirit's being. On that usage, adding "and the Son" is close to nonsense at best and heresy at worst, because it would make the Son a second ultimate source, and the Son is himself from the Father. When a Greek theologian hears the Filioque translated back into Greek as kai tou Huiou ekporeuetai, he hears a claim that the Trinity has two unoriginate origins. That reading is a fair reading of those Greek words, and no Catholic should be surprised or offended by the reaction.

The Latin Verb

Latin procedere carries no such restriction. It means to come forth, to issue, to go out from, and it can name origination from an ultimate source or a mediated coming forth through another. Latin has only this one word where Greek theology has several, so the Latin creed cannot mark the distinction the Greek creed assumes. When a Latin theologian says the Spirit procedit from the Father and the Son, he means that the Spirit comes forth from the Father through and with the Son, in one act, from one principle. The Son as a second unoriginate origin lies outside what the Latin sentence asserts.

What Follows From This

Two conclusions follow, and they cut in both directions. The first is that the Latin formula, in Latin, does not assert what the classic Greek objection takes it to assert. The second is that translating the Latin formula word for word into the Greek creed does assert something no Catholic wants to assert, which is a strong reason for the Greek text of the Creed to remain as the council wrote it. The 1995 Roman clarification discussed in section 12 makes exactly this pair of points, and it is the reason serious theologians on both sides now treat the linguistic question as load-bearing rather than as a footnote.

5. The Orthodox Theological Objection

The Orthodox theological objection rests on the monarchy of the Father, the teaching that the Father alone is the single cause and principle within the Godhead. On this account the Father is unbegotten, the Son is eternally begotten of the Father, and the Spirit eternally proceeds from the Father, and it is precisely the Father's unique role as sole source that keeps the three persons one God rather than three gods. Unity in the Trinity is secured by a person, the Father, and not by an abstract shared essence.

Given that framework, the Orthodox complaint against the Filioque is a substantive one. If the Spirit proceeds from the Father and the Son, then either there are two causes in God, which divides the Godhead, or the Son shares the Father's property of being source, which confuses the persons. Orthodox theologians have pressed both horns since Photius, and the argument is internally coherent.

The Further Orthodox Criticism

Twentieth-century Orthodox writers extended the objection beyond the doctrine of God into the doctrine of the Church. Vladimir Lossky, in The Mystical Theology of the Eastern Church, argued that subordinating the Spirit to the Son in the eternal Trinity produces a Church in which the Spirit's freedom is subordinated to institution, hierarchy and juridical order, and he read the Western development of the papacy as one long consequence. Other Orthodox theologians, including Metropolitan John Zizioulas, have been considerably more open, treating the difference as one of theological idiom that need not be church-dividing once the monarchy of the Father is safeguarded. Orthodoxy is not of one mind about how serious the Filioque is, and honest treatments say so.

What the Objection Is Not

Two misreadings are worth clearing away. Orthodoxy does not deny that the Spirit is sent by the Son in the economy of salvation, the actual history of God's dealings with the world, since that is stated plainly in the Gospel of John. Nor does Orthodoxy generally deny that the Spirit shines forth, is manifested, or proceeds through the Son, a formula found in the Greek Fathers. What Orthodoxy denies is that the Son is a cause of the Spirit's eternal existence.

6. The Orthodox Canonical Objection

The canonical objection concerns authority rather than doctrine, and it stands even for Orthodox theologians who think the Latin teaching can be given an acceptable sense. The Creed was completed by the First Council of Constantinople in 381 and received by the whole Church. The Council of Ephesus in 431, in the canon usually numbered seventh, forbade the setting forth of any other faith to rival the faith of Nicaea. The Council of Chalcedon in 451 reaffirmed the Creed of 381 as the standard text. In the Orthodox reading, those acts make the Creed conciliar property that no local church, no synod and no single bishop may amend.

On that reading, the Filioque was added to an ecumenical text by Spanish and Frankish churches, and later by Rome, none of which had the authority to amend it, and the East was never asked. Orthodox writers press that the question is one of order and honesty: if the whole Church settled the words together, the whole Church has to change them together. A Catholic who wants to answer this well has to answer the procedure as well as the doctrine.

The Catholic Answer on Procedure

Catholic theology holds that the Church can clarify a creed against a new error, since the Creed of 381 itself expanded the Creed of 325 in exactly that way, and that the Bishop of Rome has authority in matters touching the faith of the universal Church. The Catholic account of that authority rests on Matthew 16:18-19 and John 21:15-17 and is set out in our guide to the papacy and the Petrine office. Even granting all of that, the Catholic case has to reckon with the plain fact that Rome itself declined to make the addition for around two hundred years after being asked, which suggests the popes of that period did not regard the insertion as an obvious exercise of their office.

The most useful Catholic move on the canonical question is the one Rome has actually made in practice. The Creed is recited without the Filioque in the Eastern Catholic Churches of the Byzantine tradition, which are in full communion with the pope, and popes have recited the Creed in Greek without the Filioque at liturgies with Orthodox representatives present. That practice concedes the substance of the canonical point while holding the doctrine, and it is why the procedural objection has cooled considerably.

7. Photius and the Ninth-Century Quarrel

Photius, Patriarch of Constantinople in the ninth century, gave the Orthodox objection its classic literary form in his treatise Mystagogy of the Holy Spirit. Photius argued that any procession of the Spirit from the Son introduces a second cause into the Godhead and destroys the monarchy of the Father, and he pressed a series of dilemmas: if the procession from the Son is the same as from the Father, the persons are confused; if it is different, the Spirit is composite; if the Son shares in causing the Spirit, the Spirit alone is left without a share in causing anyone, which makes the Spirit less than the others.

The quarrel Photius was part of was as much about jurisdiction as about pneumatology. His own election was contested at Rome, Pope Nicholas I supported his rival Ignatius, and the two sees were simultaneously disputing whose missionaries would organize the newly christianized church in Bulgaria. In 867 Photius circulated an encyclical to the Eastern patriarchs denouncing the Filioque as taught by Frankish missionaries in Bulgaria. Politics, mission and doctrine were tangled together from the beginning, and the same tangle recurs at every later stage of the story.

The Council of 879 to 880

A council held at Constantinople in 879 to 880, with legates of Pope John VIII present, restored Photius to his see and reaffirmed the Creed of 381 without addition, prohibiting alteration of it. Orthodox theologians frequently cite this council, which some Orthodox writers number as the Eighth Ecumenical Council, as a formal condemnation of the Filioque agreed by East and West together. Catholic historians read the same acts as a reaffirmation of the Greek text of the Creed rather than a condemnation of the Latin doctrine, and they note that the Roman legates' instructions and the later Roman reception of the council are themselves disputed. The council is a genuine point of contention among historians, and it is worth naming accurately rather than claiming for one side.

What followed was not a permanent rupture. Communion between Rome and Constantinople continued after Photius, and the Filioque was one of several irritants that hardened over the following centuries into the estrangement usually dated to the events of 1054. Our guide to the Great Schism of 1054 follows that longer story, including the sack of Constantinople in 1204 that made the division bitter.

8. What the Catholic Church Actually Teaches

The Catholic Church teaches that the Holy Spirit proceeds eternally from the Father and the Son as from one single principle and by one single spiration. That formula was defined at the Second Council of Lyons in 1274, in the words tamquam ex uno principio, as from one principle, and it was reaffirmed at the Council of Florence in 1439. The whole force of the definition lies in the word "one". Catholic teaching has never held that there are two sources in God, and the definition exists precisely to exclude that reading.

How the Latin Account Works

Latin Trinitarian theology, developed most influentially by Augustine and systematized by Thomas Aquinas, distinguishes the persons of the Trinity by their relations of origin and by nothing else. The Father is Father by begetting, the Son is Son by being begotten, and the Spirit is Spirit by proceeding. On that scheme, if the Spirit were related to the Son by no relation of origin at all, there would be nothing to distinguish the Spirit from the Son, since both would simply be from the Father. The Filioque, in the Latin account, is what keeps the Spirit and the Son distinct persons rather than two names for one procession.

Augustine also supplies the image most Latin Christians know. In De Trinitate he describes the Spirit as the mutual love and communion of Father and Son, the gift in which each gives himself to the other, and he is careful to add that the Spirit proceeds from the Father principaliter, principally or as from the origin, because the Father has given the Son everything the Son has, including the Son's part in the spiration of the Spirit. That qualification is doing much more work than casual readers notice, and it is the seed of the modern Catholic clarification.

The Catechism

The Catechism of the Catholic Church sets out both traditions rather than only the Latin one. Paragraphs 246 to 248 state the Latin doctrine, recall that the Creed of 381 did not contain the formula, describe how the West came to confess it, and then say plainly that the Eastern tradition expresses first the Father's character as the first origin of the Spirit and that the Western tradition expresses first the consubstantial communion of Father and Son, and that this legitimate complementarity, provided it does not become rigid, does not affect the identity of the faith in the reality of the same mystery confessed.

9. The Scripture Both Sides Argue From

The scriptural centre of the whole dispute is a single verse, John 15:26, and both traditions quote it. Jesus tells the disciples that when the Advocate comes, whom he will send to them from the Father, the Spirit of truth who proceeds from the Father, that Spirit will testify about him. The verse names the Son as sender and the Father as the one from whom the Spirit proceeds, and everything then depends on whether the sending reveals an eternal relation or describes only what happens in time.

The Eastern Reading

Greek theology reads the verb in that verse, ekporeuetai, as naming the Spirit's eternal origin, and it observes that the verse assigns that origin to the Father and assigns the sending to the Son. On this reading the text draws precisely the distinction the East has always drawn, between the eternal procession, which is from the Father, and the temporal mission, which is from the Son. The Son sends in history the Spirit who eternally comes from the Father.

The Western Reading

Latin theology accepts that distinction and denies that it settles the matter, on the principle that the missions of the divine persons in time reveal their eternal relations, since God does not act in history other than as he eternally is. The Son can only send the Spirit if the Spirit is in some real sense the Son's own. Other texts are read the same way: Jesus breathes on the disciples and says "Receive the Holy Spirit" (John 20:22); he tells them that if he goes he will send the Advocate to them (John 16:7); Paul calls the Spirit "the Spirit of his Son" (Galatians 4:6) and "the Spirit of Christ" (Romans 8:9); and the Spirit takes what belongs to the Son and declares it (John 16:14-15).

The honest assessment is that Scripture does not settle the question on its own, and that each tradition is reading the same verses through a prior account of how eternity and history are related. Orthodox readers say the West is projecting the economy back into the immanent Trinity. Western readers say the East is severing the revelation from the reality it reveals. If you want the underlying doctrine of the third person rather than this one clause, our guide to the Holy Spirit covers his person, work and gifts.

10. What the Fathers Said, East and West

The patristic evidence is genuinely mixed, which is why the argument has lasted. Both traditions can cite Fathers, and neither can cite a unanimous consent that settles the matter. Reading the Fathers here requires attention to what each writer was arguing against and to which language he wrote in.

The Greek Fathers

The Cappadocians, Basil the Great, Gregory of Nazianzus and Gregory of Nyssa, establish the framework the East has kept: the Father is the sole source, the Son is begotten, the Spirit proceeds, and the distinction between begetting and procession is confessed without being explained. Gregory of Nyssa writes of the Spirit as being from the Father and as being of the Son, and speaks of the Son as intervening in the order of the persons. Cyril of Alexandria repeatedly calls the Spirit the Spirit of the Son, proper to the Son, poured out through the Son, and Latin theologians have cited Cyril heavily. Orthodox theologians answer that these expressions concern manifestation and consubstantiality rather than causation, and that "through the Son" (dia tou Huiou) is precisely the formula that keeps the Father as sole cause.

Maximus the Confessor

One of the most quoted texts in the modern discussion is a letter of Maximus the Confessor to a priest named Marinus, written in the seventh century. Greeks had complained about a Latin usage, and Maximus, a Greek who was living in the West, defended the Latins by explaining that they did not make the Son a cause of the Spirit. He wrote that they cited the Roman Fathers and Cyril of Alexandria to show that the Spirit proceeds from the Father through the Son in respect of essence, and that they acknowledged the Father as the one cause of the Son and of the Spirit. Catholics read this as a Greek saint certifying the Latin doctrine as orthodox once properly understood. Orthodox readers point out that Maximus defends a Latin usage he understood to mean "through the Son", not the later Latin claim that the Son is a principle of the Spirit. Both observations are true, and the letter remains one of the strongest bridges in the sources.

The Latin Fathers

Ambrose, Augustine, Hilary of Poitiers and Leo the Great all speak of the Spirit as proceeding from the Father and the Son, and they do so long before the phrase appears in any creed. Augustine's De Trinitate is the decisive text for the Latin tradition, and the qualification noted above, that the Spirit proceeds from the Father principally because the Father gave the Son all that he has, shows that the Latin Fathers were not asserting two independent origins. The Athanasian Creed, a Western text despite its name, states the doctrine formally.

11. Lyons 1274 and Florence 1439

Two medieval councils tried to settle the Filioque as part of a general reunion of East and West, and both agreements collapsed on reception in the East. Their texts are still the most formal Catholic statements of the doctrine, and their failure is still the most instructive part of the story.

The Second Council of Lyons, 1274

At Lyons the Byzantine Emperor Michael VIII Palaiologos, under severe political pressure from Western powers who wished to retake Constantinople, sent a delegation that accepted the Latin position, including papal primacy and the Filioque. The council defined that the Holy Spirit proceeds eternally from the Father and the Son as from one principle and by one single spiration, and it ruled out in those same words any reading that would make two principles or two spirations. That phrase, one principle and one spiration, is the heart of Catholic teaching on the question. The union was rejected by the Byzantine clergy and people, who saw it as sold for military protection, and it was repudiated after Michael's death in 1282.

The Council of Ferrara-Florence, 1439

Florence was a far more serious theological effort. The Greek delegation was large and included the emperor and the patriarch, the sessions on the Filioque ran for months, and the debates were substantive, with Bessarion of Nicaea eventually persuaded that the Greek and Latin formulas expressed one faith. The bull of union, Laetentur Caeli, declared that the Latin "from the Son" and the Greek "through the Son" mean the same thing, that the Spirit is from the Father and the Son eternally and has his essence from both as from one principle and one spiration, and it permitted the addition to the Creed as lawfully made. Almost all the Greek delegates signed. Mark of Ephesus refused, and he is honoured as a saint in the Orthodox Church for that refusal.

The union failed on reception at home. Clergy and laity in Constantinople rejected it, several of the signatories repudiated their signatures, and the fall of the city to the Ottomans in 1453 ended the matter. Florence matters here for two reasons. It shows that serious and sustained attempts have been made to resolve the difference. It also shows that in Orthodox ecclesiology a council that the body of the faithful does not receive has not decided anything, which is itself one of the open questions between the two Churches.

Both councils are counted as ecumenical by the Catholic Church and are not recognized as ecumenical by the Eastern Orthodox Churches. The account above of Orthodox rejection follows the standard narrative in both Catholic and Orthodox historical writing.

12. The 1995 Clarification and What It Conceded

The key modern Catholic statement on the Filioque is a 1995 document from the Pontifical Council for Promoting Christian Unity titled The Greek and Latin Traditions Regarding the Procession of the Holy Spirit. It was published in L'Osservatore Romano and framed as a clarification offered to advance the dialogue with Orthodoxy. It is short, and it moved the question further than anything since Florence.

What It Says

The clarification affirms that the Father alone is the source without source of the whole Trinity, the sole cause of both the Son and the Spirit. It states that the Greek verb ekporeuesthai, used in the Creed of 381, signifies origination from the Father as the ultimate cause, and that the Latin procedere is a broader term that does not carry that restriction. It follows that the Catholic doctrine, expressed in Latin, does not and cannot mean that the Spirit takes origin from the Son as from an unoriginate source, and that the Latin formula should never be translated into Greek in a way that would say so. It presents the Latin and Greek traditions as complementary expressions of one faith, and it commends the practice of reciting the Creed in Greek in its original conciliar form.

Read carefully, the document grants the substance of what the Eastern objection was defending. The monarchy of the Father is affirmed without qualification. The Greek text of the Creed is treated as the normative conciliar text. The Latin usage is defended as a legitimate way of saying, in a language with fewer distinctions, something that does not contradict the Greek.

The 2003 North American Consultation

In 2003 the North American Orthodox-Catholic Theological Consultation, a long-running joint body of Catholic and Orthodox theologians in the United States and Canada, issued an agreed statement titled The Filioque: A Church-Dividing Issue?. It reviewed the history and the theology at length and recommended, among other things, that the Catholic Church use the original Greek text of the Creed of 381 as the basis for translations of it in catechesis and liturgy, that theologians on both sides stop labelling the other tradition's teaching on the procession as heretical, and that the difference need not remain church-dividing. The statement is the work of a regional consultation and binds neither Church, and it represents the settled judgement of a serious body of theologians from both traditions.

The 1995 text is the clarification of the Pontifical Council for Promoting Christian Unity, published in L'Osservatore Romano in September 1995. The 2003 text is an agreed statement of the North American Orthodox-Catholic Theological Consultation and carries the authority of that consultation only.

Practice Following Doctrine

Alongside the documents there has been a quiet change in practice. The Eastern Catholic Churches of the Byzantine tradition recite the Creed without the Filioque, with Rome's explicit approval, and Rome has discouraged its introduction into Eastern Catholic usage. Popes have recited the Creed in Greek without the Filioque at liturgies attended by Orthodox delegations. That practice says, without a formal decree, that the Latin Church can hold its doctrine while leaving the conciliar text alone.

13. Who Says the Filioque Today

The Filioque is confessed today by the Latin Rite of the Catholic Church and by most Western Protestant bodies that inherited the Latin liturgical text, and it is not confessed by the Eastern Churches or by a growing number of Western churches that have removed it deliberately. Knowing who says what prevents a great deal of confusion in conversation.

This table describes official liturgical texts and general practice. Individual provinces, synods and parishes vary, particularly among Anglicans and Protestants where service books often permit either form.

One further note for anyone reading about this online. Some Western commentators treat the Filioque as a curiosity that only academics care about. Eastern Christians generally do not experience it that way, since for them it touches the doctrine of God and the integrity of a conciliar text at the same time. Taking the objection seriously costs a Catholic nothing and earns the right to be heard.

14. Does the Filioque Still Divide the Churches?

The Filioque remains one of the open questions between Rome and the Eastern Orthodox Churches, and it is no longer the hardest of them. Papal primacy and jurisdiction now occupy that place in the dialogue, followed by the definitions of the First Vatican Council and the Immaculate Conception. The Filioque has moved because both sides have accepted that the linguistic difference is real and that the Father's sole causality is not in dispute.

What Has Actually Been Settled

Three things are settled in the formal dialogue. The Father alone is the origin without origin, affirmed on the Catholic side in 1995. The Greek conciliar text of the Creed is the normative text and should be recited without addition in Greek. The Latin formula is not a claim of two ultimate sources, whatever its historical wording may have suggested to Greek readers. On each of those points the two traditions now say the same thing.

What Is Not Settled

Two things are not settled. The first is whether the Son plays any real part in the eternal procession of the Spirit at all, or only in the Spirit's manifestation and mission, which is a genuine doctrinal difference in its own right and goes beyond wording. The second is the canonical question of who may amend a conciliar creed, which is the primacy question wearing different clothes. Progress on the Filioque is therefore bounded by progress on authority, which is the pattern across the whole Catholic and Orthodox dialogue described in our guide to ecumenism.

What a Reader Should Do With This

Say the Creed with attention, whichever form your Church uses, and know what the words carry. Learn the Eastern objection well enough to state it in a way an Orthodox Christian would accept as fair, because most Catholic accounts of it are caricatures. Hold the Catholic doctrine plainly: one principle, one spiration, the Father the origin without origin. Pray for the unity Christ asked for in John 17:21. And do not let a page about a Latin adverb-and-noun substitute for actually praying to the Holy Spirit, which is the point of confessing him at all.

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