Orthodox Christianity and Roman Catholicism: Major Differences

Eastern Orthodoxy and Roman Catholicism share a common heritage of the first millennium but diverged over fundamental issues of authority, Trinitarian theology, and the nature of grace. The central disputes concern the Filioque, papal primacy and infallibility, the nature of created vs. uncreated grace, and ecclesiology. While both traditions share the seven sacraments, apostolic succession, and veneration of saints, the theological frameworks undergirding these practices differ significantly. This comparison is written from within the Orthodox Church: the Roman Catholic positions are reported accurately, in their own terms, but the distinctive Roman doctrines are presented as what they are for the Church – teachings she has examined and not received.

Tradition: Pan-Orthodox

The Filioque

The Filioque (“and the Son”) is the most important dogmatic disagreement between East and West. The original Niceno-Constantinopolitan Creed (381) confesses that the Holy Spirit “proceeds from the Father.” The Western Church added “and the Son” (Filioque), gradually introducing this into the Creed from the sixth century onward and formally adopting it in Rome in 1014.

The Orthodox Church rejects the Filioque as both:

  • A theological error that compromises the monarchy of the Father in the Trinity
  • A canonical violation – unilateral alteration of a Creed fixed by Ecumenical Council

For detailed treatment, see The Filioque Controversy.

Papal Primacy and Infallibility

The Roman Catholic Position

The First Vatican Council (1870) defined two dogmas in its constitution Pastor Aeternus:

  1. Papal primacy of jurisdiction: The Pope possesses “full and supreme power of jurisdiction over the whole Church, not only in things pertaining to faith and morals, but also in those which pertain to the discipline and government of the Church throughout the whole world” (Pastor Aeternus, ch. 3).

  2. Papal infallibility: “The Roman Pontiff, when he speaks ex cathedra – that is, when in the exercise of his office as pastor and teacher of all Christians, by virtue of his supreme apostolic authority, he defines a doctrine regarding faith or morals to be held by the whole Church – he possesses, by the divine assistance promised to him in blessed Peter, that infallibility which the divine Redeemer willed his Church to enjoy in defining doctrine concerning faith or morals” (Pastor Aeternus, ch. 4).

The Second Vatican Council (Lumen Gentium, 1964) situated papal primacy within the college of bishops but did not diminish the claims of Vatican I.

The Orthodox Position

The Orthodox Church acknowledges that the Bishop of Rome held a primacy of honor (presbeia tes times) in the first millennium – he was the “first among equals” of the five patriarchs. This primacy is grounded in:

  • The political importance of Rome as the imperial capital
  • The apostolic foundation of the Roman see by Peter and Paul
  • Ancient custom confirmed by the canons

However, the Orthodox reject the Roman claims to:

Universal jurisdiction: Apostolic Canon 34 establishes that a primate acts in concert with his fellow bishops, not over them. Canon 6 of Nicaea I confirms the prerogatives of major sees but does not grant Rome jurisdiction over the whole Church. Canon 28 of Chalcedon explicitly grounds the rank of sees in their political, not theological, significance: “The Fathers rightly granted privileges to the throne of Old Rome because it was the royal city.”

Infallibility: The Orthodox Church recognizes infallibility only in the Ecumenical Council guided by the Holy Spirit, confirmed by the reception of the whole Church. No individual bishop, however exalted, possesses personal infallibility. Popes have in fact erred: Pope Honorius I (d. 638) was anathematized by name as a Monothelite by the Third Council of Constantinople – in its thirteenth session (March 28, 681) and again in its definition of faith – “because we have found by his letter to Sergius that he followed his opinion in all things and confirmed his wicked dogmas” (Acts of Constantinople III, Session 13 and Definition [NPNF II/14]).

Direct divine institution: Rome claims that papal primacy derives from Christ’s commission to Peter (Matthew 16:18-19). The Orthodox Fathers interpret this passage differently – Peter’s confession of faith is the “rock,” and the authority to bind and loose was given to all the apostles (Matthew 18:18; John 20:23). Papal primacy is a matter of canonical order, not divine right.

Orthodox theologians who have addressed this include:

  • St. Photius the Great (9th century), who rejected papal claims in his encyclical of 867
  • Metropolitan Maximos of Sardis, The Oecumenical Patriarchate in the Orthodox Church: A Study in the History and Canons of the Church, trans. Gamon McLellan, Analecta Vlatadon 24 (Thessaloniki: Patriarchal Institute for Patristic Studies, 1976)
  • John Meyendorff, Byzantium and the Rise of Russia (1981) and other works
  • Alexander Schmemann, The Historical Road of Eastern Orthodoxy (1963)

The Modern Dialogue on Primacy

Primacy is the central agenda of the Joint International Commission for Theological Dialogue between the Roman Catholic Church and the Orthodox Church (established 1979). Two agreed documents are particularly significant:

  • The Ravenna Document (October 13, 2007), Ecclesiological and Canonical Consequences of the Sacramental Nature of the Church: Ecclesial Communion, Conciliarity and Authority, in which both sides agreed that the Church has a protos (first) at the local, regional, and universal levels, and that in the first millennium the bishop of Rome was the protos among the patriarchs – while recording that they “disagree, however, on the interpretation of the historical evidence from this era regarding the prerogatives of the bishop of Rome as protos” (Ravenna Document §41). The Moscow Patriarchate’s delegation withdrew from the Ravenna session (over the participation of the Constantinople-sponsored Estonian church) and did not subscribe to the document.
  • The Chieti Document (September 21, 2016), Synodality and Primacy during the First Millennium: Towards a Common Understanding in Service to the Unity of the Church, adopted with Moscow participating, which describes first-millennium Roman primacy as exercised in communion and synodality, with appeals to Rome functioning canonically rather than as universal jurisdiction.

These texts agree on a universal taxis (order) with Rome as first, but the nature of that primacy – honor and service in synodality (Orthodox) versus jurisdiction by divine institution (Vatican I) – remains the unresolved core of the dispute.

The Immaculate Conception

The Roman Catholic Dogma

In 1854, Pope Pius IX defined the dogma of the Immaculate Conception (Ineffabilis Deus): the Blessed Virgin Mary “in the first instant of her conception, by a singular privilege and grace granted by God, in view of the merits of Jesus Christ, the Savior of the human race, was preserved exempt from all stain of original sin.”

The Orthodox Response

The Orthodox Church deeply venerates the Theotokos (Mother of God) and affirms her exceptional holiness. However, the Orthodox reject the dogma of the Immaculate Conception on several grounds:

  1. It is unnecessary: The Orthodox understanding of ancestral sin differs from the Augustinian concept of original sin (inherited guilt). In Orthodox theology, humanity inherits the consequences of Adam’s sin (mortality, a tendency toward sin) but not Adam’s personal guilt. Since there is no inherited guilt to be exempted from, the Immaculate Conception solves a problem that does not exist in Orthodox theology.

  2. It separates Mary from the rest of humanity: If Mary was preserved from the common human condition from the moment of her conception, her free cooperation with God’s grace (synergeia) is diminished. The Orthodox prefer to emphasize Mary’s purification by the Holy Spirit, particularly at the Annunciation.

  3. It was defined unilaterally: It was proclaimed as dogma by a single bishop (the Pope) without an Ecumenical Council, which the Orthodox regard as the only competent authority for defining dogma.

  4. It lacks patristic support: While some Latin Fathers moved in this direction, the patristic tradition as a whole does not support the notion of an exemption from the common human condition at the moment of conception. Notable Western theologians opposed the idea before its definition: Bernard of Clairvaux objected to the new feast of Mary’s conception (Letter 174, to the canons of Lyons), and Thomas Aquinas taught that Mary was sanctified in the womb after animation, not preserved from original sin at conception (Summa Theologiae III, q. 27, a. 2) – though some later Thomists have read his position as compatible with the dogma as defined.

The Orthodox affirm that Mary was the most holy of all human beings, prepared by God through generations (the “forefeast” of the Nativity of the Theotokos), and purified by the Holy Spirit, but within the common human condition rather than exempt from it.

Purgatory and the State of the Dead

The Roman Catholic Doctrine

Roman Catholicism teaches the existence of purgatory – a state of purification after death in which souls destined for heaven undergo cleansing of the temporal punishment due to sins already forgiven. This was defined at the Councils of Florence (1439) and Trent (1563). The theological framework involves a distinction between the eternal punishment of sin (remitted in absolution) and temporal punishment (requiring satisfaction).

The Orthodox Position

The Orthodox Church rejects purgatory as a distinct state of purifying punishment. However, the Orthodox do pray for the dead and believe that the state of the departed can be affected by the prayers of the living and the Eucharistic sacrifice offered on their behalf. The key differences are:

  • The Orthodox reject the juridical framework of “satisfaction” for temporal punishment
  • There is no concept of a “purifying fire” (the Latin ignis purgatorius) in Orthodox theology
  • The Orthodox understanding is more apophatic: we commend the departed to God’s mercy without specifying the precise mechanism of their post-mortem purification
  • The prayers of the Church, the Divine Liturgy, and memorial services (panikhidy) benefit the departed, but Orthodox theology does not systematize this into a doctrine of purgatory

The aerial toll-houses (mytarstva) are a concept found in certain Orthodox sources – most fully in the account of Theodora’s passage in the Life of St. Basil the New, written by the saint’s disciple Gregory in 10th-century Constantinople (critical edition and translation: Sullivan, Talbot, and McGrath, The Life of Saint Basil the Younger, Dumbarton Oaks Studies 45, 2014) – describing the soul’s journey after death through a series of “toll-houses” where demons accuse the soul of specific sins. This concept is:

  • Debated within Orthodoxy: some theologians accept it as part of Tradition; others reject it as apocryphal or allegorical
  • Not dogmatically defined: it has never been promulgated by an Ecumenical Council
  • Defended by some ROCOR theologians: Hieromonk Seraphim (Rose) wrote extensively in defense of the toll-houses in The Soul After Death (1980), ch. 6
  • Qualified or criticized by others: Metropolitan Macarius (Bulgakov) of Moscow, while including the teaching in his dogmatics, cautioned that the toll-house imagery “must be understood… as far as possible in a spiritual sense” and not crudely literally (quoted in Pomazansky, Orthodox Dogmatic Theology, appendix on the toll-houses); it was attacked outright by Deacon Lev Puhalo in the polemics of the late 1970s-1980s (Puhalo, The Soul, the Body and Death, 1980), a dispute the ROCOR Synod ordered ended in 1980 without dogmatizing the doctrine

Created Grace vs. Uncreated Grace

The Roman Catholic Position

In the dominant scholastic tradition (following Thomas Aquinas), grace is understood as a created gift bestowed by God upon the soul – gratia creata. It is a real quality infused into the soul that enables it to participate in the supernatural order. The distinction is between God in His essence (absolutely inaccessible) and grace as a created intermediary.

The Orthodox Position

Following St. Gregory Palamas (1296-1359) and the Hesychast Councils of the 14th century (Constantinople, 1341, 1347, 1351), the Orthodox Church teaches the essence-energies distinction: God is absolutely unknowable in His essence, but truly communicates Himself through His uncreated energies (aktistos energeia). Grace is not a created effect but God Himself acting and communicating Himself to creation.

This distinction has enormous consequences:

  • Theosis (deification) is real participation in God’s uncreated energies, not merely a metaphor or a sharing in created gifts
  • The light of Tabor that the apostles saw at the Transfiguration was the uncreated light of God’s glory, not a created phenomenon
  • There is no ontological gap between God and humanity filled by a created intermediary; God Himself bridges the gap through His energies
  • This preserves both God’s absolute transcendence (in essence) and His real immanence (in energies)

The Roman Catholic tradition has generally not accepted the Palamite distinction, viewing it as introducing a real division within God (Lossky, The Mystical Theology of the Eastern Church, ch. 4; Meyendorff, A Study of Gregory Palamas, 1959).

Sacramental Theology

While both traditions maintain seven sacraments (or “mysteries” in Orthodox usage), there are notable differences:

The Epiclesis vs. Words of Institution

  • Roman Catholic: The words of institution (“This is My Body… This is My Blood”) are the essential “form” of the Eucharistic consecration, following Aristotelian hylomorphic analysis. The bread and wine are changed at the moment of the priest’s recitation of Christ’s words.
  • Orthodox: The epiclesis (invocation of the Holy Spirit upon the gifts) is the essential moment of consecration. The Orthodox have generally resisted pinpointing a single “moment of consecration,” understanding the entire anaphora (Eucharistic prayer) as consecratory, but the epiclesis is seen as the culminating action. The Orthodox reject the scholastic hylomorphic framework.

Transubstantiation

  • Roman Catholic: The Fourth Lateran Council (1215) and the Council of Trent formally adopted the term transubstantiation to describe the change: the substance of bread and wine is converted into the substance of Christ’s Body and Blood, while the accidents (appearances) remain.
  • Orthodox: The Orthodox affirm the real change of the bread and wine into Christ’s Body and Blood but have not dogmatically adopted the Aristotelian terminology of transubstantiation. Some Orthodox theologians (particularly in the 17th-century Latinizing period) used the term, and the term metousiosis (change of substance) appears in the Confession of Dositheus, adopted by the Synod of Jerusalem (1672), Decree 17. However, many Orthodox theologians today prefer to speak of the mystery without committing to Aristotelian categories.

Other Sacramental Differences

  • Baptism: Orthodox practice triple immersion; Roman Catholic practice has moved predominantly to pouring (affusion) or sprinkling (aspersion). The Orthodox consider full immersion the proper form.
  • Chrismation/Confirmation: In Orthodoxy, chrismation is administered immediately after baptism, even to infants, who then receive communion. In Roman Catholicism, confirmation is typically delayed until later childhood or adolescence.
  • Communion: Orthodox give communion to baptized infants; Roman Catholics require the “age of reason.” Orthodox communion is always in both kinds (bread and wine); the Roman practice of communion under one kind (bread only) for the laity, though now less common, was long standard.

Ecclesiology

  • Orthodox: The Church is governed by the college of bishops in council, with the Ecumenical Patriarch holding a primacy of honor. No single bishop has universal jurisdiction. The Ecumenical Council is the highest authority.
  • Roman Catholic: The Pope holds full, supreme, and universal jurisdiction over the whole Church. He is the Vicar of Christ and the successor of Peter. While Vatican II emphasized the college of bishops, the Pope’s authority is supreme and can be exercised independently of any council.

For more on ecclesiology, see Church Governance.

Other Differences

Calendar

Most Orthodox churches use the Julian calendar (13 days behind the Gregorian calendar as of the 21st century) for the calculation of Pascha (Easter) and many for the fixed feasts. Some Orthodox churches (Constantinople, Greece, Romania, Bulgaria, Antioch, and others) adopted the Revised Julian calendar for fixed feasts while retaining the Julian Paschalion. The Roman Catholic Church uses the Gregorian calendar (adopted 1582).

ROCOR uses the Julian calendar for all purposes.

Married Clergy

  • Orthodox: Married men may be ordained as deacons and priests (but not bishops). Marriage after ordination is forbidden. Bishops are drawn from the monastic clergy.
  • Roman Catholic (Latin Rite): Clerical celibacy is required for priests and deacons (permanent deacons excepted). Eastern Catholic churches within Rome’s communion generally permit married priests.

Divorce and Remarriage

  • Orthodox: The Church permits divorce and remarriage (up to three marriages) by pastoral economy, recognizing human weakness.
  • Roman Catholic: Marriage is indissoluble. Divorce is not recognized; only annulment (declaration that a valid marriage never existed) permits remarriage.

Original Sin / Ancestral Sin

  • Roman Catholic: Following Augustine, original sin involves inherited guilt as well as a disordered nature. Baptism removes the guilt of original sin.
  • Orthodox: Ancestral sin (progoniki amartia) involves inherited mortality and corruption but not personal guilt for Adam’s sin. This difference underlies the disagreement over the Immaculate Conception.

See Also

References

  • First Vatican Council, Pastor Aeternus (1870)
  • Second Vatican Council, Lumen Gentium (1964)
  • Pope Pius IX, Ineffabilis Deus (1854)
  • Council of Trent, Session 13 (1551) on the Eucharist; Session 25 (1563), Decree on Purgatory
  • Council of Florence, Laetentur Caeli (1439)
  • Confession of Dositheus, Synod of Jerusalem (1672), Decree 17
  • Apostolic Canon 34
  • Canon 6 of Nicaea I; Canon 28 of Chalcedon
  • Third Council of Constantinople (680-681), Session 13 and Definition of Faith (condemnation of Pope Honorius), trans. NPNF II/14
  • Joint International Commission for Theological Dialogue, Ravenna Document (October 13, 2007) and Chieti Document (September 21, 2016)
  • Metropolitan Maximos of Sardis, The Oecumenical Patriarchate in the Orthodox Church, trans. Gamon McLellan, Analecta Vlatadon 24 (Thessaloniki: Patriarchal Institute for Patristic Studies, 1976)
  • Sullivan, Talbot, and McGrath (eds. and trans.), The Life of Saint Basil the Younger, Dumbarton Oaks Studies 45 (2014)
  • Thomas Aquinas, Summa Theologiae III, q. 27; Bernard of Clairvaux, Letter 174
  • Vladimir Lossky, The Mystical Theology of the Eastern Church (1944)
  • John Meyendorff, A Study of Gregory Palamas (1959)
  • John Meyendorff, Byzantine Theology (1974)
  • Hieromonk Seraphim (Rose), The Soul After Death (1980)
  • St. Gregory Palamas, Triads in Defense of the Holy Hesychasts
  • St. Photius the Great, Mystagogy of the Holy Spirit
  • Kallistos Ware, The Orthodox Church (revised editions)