An ecumenical council (or oecumenical council; also general council) is a conference of ecclesiastical dignitaries and theological experts convened to discuss and settle matters of Church doctrine and practice in which those entitled to vote are convoked from the whole world (oikoumene) and which secures the approbation of the whole Church.
The word "ecumenical" derives from the Late Latin oecumenicus "general, universal", from Greek oikoumenikos "from the whole world", from he oikoumene ge "the inhabited world (as known to the ancient Greeks); the Greeks and their neighbors considered as developed human society (as opposed to barbarian lands)", in later use "the Roman world" and in the Christian sense in ecclesiastical Greek, from oikoumenos, present passive participle of oikein "inhabit", from oikos "house, habitation." The first seven Ecumenical Councils, recognised by both the eastern and western denominations comprising Chalcedonian Christianity, were convoked by Christian Roman Emperors, who also enforced the decisions of those councils within the state church of the Roman Empire.
Starting with the third ecumenical council, noteworthy schisms led to non-participation by some members of what had previously been considered a single Christian Church. Thus, some parts of Christianity did not attend later councils, or attended but did not accept the results. Bishops belonging to what became known as the Eastern Orthodox Church accept only seven ecumenical councils, as described below. Bishops belonging to what became known as the Church of the East only participated in the first two councils. Bishops belonging to what became known as Oriental Orthodoxy participated in the first four councils, but rejected the decisions of the fourth and did not attend any subsequent ecumenical councils.
Acceptance of councils as ecumenical and authoritative varies between different Christian denominations. Disputes over christological and other questions have led certain branches to reject some councils that others accept.
The Church of the East (accused by others of adhering to Nestorianism) accepts as ecumenical only the first two councils. Oriental Orthodox Churches accept the first three. Both the Eastern Orthodox Church and Roman Catholic Church recognise as ecumenical the first seven councils, held from the 4th to the 9th century. While the Eastern Orthodox Church accepts no later council or synod as ecumenical, the Roman Catholic Church continues to hold general councils of the bishops in full communion with the Pope, reckoning them as ecumenical. In all, the Roman Catholic Church recognises twenty-one councils as ecumenical. Anglicans and confessional Protestants accept either the first seven or the first four as ecumenical councils.
The doctrine of the infallibility of ecumenical councils states that solemn definitions of ecumenical councils, which concern faith or morals, and to which the whole Church must adhere, are infallible. Such decrees are often labeled as 'Canons' and they often have an attached anathema, a penalty of excommunication, against those who refuse to believe the teaching. The doctrine does not claim that every aspect of every ecumenical council is dogmatic, but that every aspect of an ecumenical council is free of errors or is indefectible.
Both the Eastern Orthodox and the Roman Catholic churches uphold versions of this doctrine. However, the Roman Catholic Church holds that solemn definitions of ecumenical councils meet the conditions of infallibility only when approved by the Pope, while the Eastern Orthodox Church holds that an ecumenical council is itself infallible when pronouncing on a specific matter.
Protestant churches would generally view ecumenical councils as fallible human institutions that have no more than a derived authority to the extent that they correctly expound Scripture (as most would generally consider occurred with the first four councils in regard to their dogmatic decisions).
Church councils were, from the beginning, bureaucratic exercises. Written documents were circulated, speeches made and responded to, votes taken, and final documents published and distributed. A large part of what is known about the beliefs of heresies comes from the documents quoted in councils in order to be refuted, or indeed only from the deductions based on the refutations.
Most councils dealt not only with doctrinal but also with disciplinary matters, which were decided in canons ("laws"). Study of the canons of church councils is the foundation of the development of canon law, especially the reconciling of seemingly contradictory canons or the determination of priority between them. Canons consist of doctrinal statements and disciplinary measures - most Church councils and local synods dealt with immediate disciplinary concerns as well as major difficulties of doctrine. Eastern Orthodoxy typically views the purely doctrinal canons as dogmatic and applicable to the entire church at all times, while the disciplinary canons apply to a particular time and place and may or may not be applicable in other situations.
Of the seven councils recognised in whole or in part by both the Roman Catholic and the Eastern Orthodox Church as ecumenical, all were called by a Roman emperor. The emperor gave them legal status within the entire Roman Empire. All were held in the eastern part of the Roman Empire. The bishop of Rome (self-styled as "pope" since the end of the fourth century) did not attend, although he sent legates to some of them.
Church councils were traditional and the ecumenical councils were a continuation of earlier councils (also known as synods) held in the Empire before Christianity was made legal. These include the Council of Jerusalem (c. 50), the Council of Rome (155), the Second Council of Rome (193), the Council of Ephesus (193), the Council of Carthage (251), the Council of Iconium (258), the Council of Antioch (264), the Councils of Arabia (246-247), the Council of Elvira (306), the Council of Carthage (311), the Synod of Neo-Caesarea (c. 314), the Council of Ancyra (314) and the Council of Arles (314).
The first seven councils recognised in both East and West as ecumenical and several others to which such recognition is refused were called by the Byzantine emperors. In the first millennium, various theological and political differences such as Nestorianism or Dyophysitism caused parts of the Church to separate after councils such as those of Ephesus and Chalcedon, but councils recognised as ecumenical continued to be held.
The Council of Hieria of 754, held at the imperial palace of that name close to Chalcedon in Anatolia, was summoned by Byzantine Emperor Constantine V and was attended by 338 bishops, who regarded it as the seventh ecumenical council The Second Council of Nicaea, which annulled that of Hieria, was itself annulled at a synod held in 815 in Constantinople under Emperor Leo V. This synod, presided over by Patriarch Theodotus I of Constantinople, declared the Council of Hieria to be the seventh ecumenical council, but, although the Council of Hieria was called by an emperor and confirmed by another, and although it was held in the east, it later ceased to be considered ecumenical.
Similarly, the Second Council of Ephesus of 449, also held in Anatolia, was called by the Byzantine Emperor Theodosius II and, though annulled by the Council of Chalcedon, was confirmed by Emperor Basiliscus, who annulled the Council of Chalcedon. This too ceased to be considered an ecumenical council.
The Roman Catholic Church does not consider the validity of an ecumenical council's teaching to be in any way dependent on where it is held or on the granting or withholding of prior authorization or legal status by any state, in line with the attitude of the 5th-century bishops who "saw the definition of the church's faith and canons as supremely their affair, with or without the leave of the Emperor" and who "needed no one to remind them that Synodical process pre-dated the Christianisation of the royal court by several centuries".
The Roman Catholic Church recognizes as ecumenical various councils held later than the First Council of Ephesus (after which churches out of communion with the Holy See because of the Nestorian Schism did not participate), later than the Council of Chalcedon (after which there was no participation by churches that rejected Dyophysitism), later than the Second Council of Nicaea (after which there was no participation by the Eastern Orthodox Church), and later than the Fifth Council of the Lateran (after which groups that adhered to Protestantism did not participate).
Of the twenty-one ecumenical councils recognised by the Roman Catholic Church, some gained recognition as ecumenical only later. Thus the Eastern First Council of Constantinople became ecumenical only when its decrees were accepted in the West also.
In the history of Christianity, the first seven ecumenical councils, from the First Council of Nicaea (325) to the Second Council of Nicaea (787), represent an attempt to reach an orthodox consensus and to unify Christendom.
All of the original seven ecumenical councils as recognised in whole or in part were called by an emperor of the Eastern Roman Empire and all were held in the Eastern Roman Empire, a recognition denied to other councils similarly called by an Eastern Roman emperor and held in his territory, in particular the Second Council of Ephesus (449) and the Council of Hieria (754), which saw themselves as ecumenical.
As late as the 11th century, only seven councils were recognised as ecumenical in the Roman Catholic Church. Then, in the time of Pope Gregory VII (1073-1085), canonists who in the Investiture Controversy quoted the prohibition in canon 22 of the Council of Constantinople of 869-870 against laymen influencing the appointment of prelates elevated this council to the rank of ecumenical council.[unreliable source?] Only in the 16th century was recognition as ecumenical granted by Catholic scholars to the Councils of the Lateran, of Lyon and those that followed. The following is a list of further councils generally recognised as ecumenical by Roman Catholic theologians:
Eastern Orthodox catechisms teach that there are seven ecumenical councils and there are feast days for seven ecumenical councils. Nonetheless, some Eastern Orthodox consider the Council of Constantinople of 879-880, that of Constantinople in 1341-1351 and that of Jerusalem in 1672 to be ecumenical:
It is unlikely that formal ecumenical recognition will be granted to these councils, despite the acknowledged orthodoxy of their decisions, so that only seven are universally recognized among the Eastern Orthodox as ecumenical.
Although some Protestants reject the concept of an ecumenical council establishing doctrine for the entire Christian faith, Roman Catholics, Lutherans, Anglicans, Eastern Orthodox and Oriental Orthodox all accept the authority of ecumenical councils in principle. Where they differ is in which councils they accept and what the conditions are for a council to be considered "ecumenical". The relationship of the Papacy to the validity of ecumenical councils is a ground of controversy between Roman Catholicism and the Eastern Orthodox Churches. The Roman Catholic Church holds that recognition by the Pope is an essential element in qualifying a council as ecumenical; Eastern Orthodox view approval by the Bishop of Rome (the Pope) as being roughly equivalent to that of other patriarchs. Some have held that a council is ecumenical only when all five patriarchs of the Pentarchy are represented at it. Others reject this theory in part because there were no patriarchs of Constantinople and Jerusalem at the time of the first ecumenical council.
The Church of the East accepts two ecumenical councils, the First Council of Nicaea and the First Council of Constantinople. It was the formulation of Mary as the Theotokos which caused a schism with the Church of the East, now divided between the Assyrian Church of the East and the Ancient Church of the East, while the Chaldean Catholic Church entered into full communion with Rome in the 16th century. Meetings between Pope John Paul II and the Assyrian Patriarch Mar Dinkha IV led to a common Christological declaration on 11 November 1994 that "the humanity to which the Blessed Virgin Mary gave birth always was that of the Son of God himself". Both sides recognised the legitimacy and rightness, as expressions of the same faith, of the Assyrian Church's liturgical invocation of Mary as "the Mother of Christ our God and Saviour" and the Catholic Church's use of "the Mother of God" and also as "the Mother of Christ".
Oriental Orthodoxy accepts three ecumenical councils, the First Council of Nicaea, the First Council of Constantinople, and the Council of Ephesus. The formulation of the Chalcedonian Creed caused a schism in the Alexandrian and Syriac churches. Reconciliatory efforts between Oriental Orthodox with the Eastern Orthodox and the Catholic Church in the mid- and late-20th century have led to common Christological declarations. The Oriental and Eastern Churches have also been working toward reconciliation as a consequence of the ecumenical movement.
The Oriental Orthodox hold that the Dyophysite formula of two natures formulated at the Council of Chalcedon is inferior to the Miaphysite formula of "One Incarnate Nature of God the Word" (Byzantine Greek: Mia physis tou theou logou sarkousomene) and that the proceedings of Chalcedon themselves were motivated by imperial politics. The Alexandrian Church, the main Oriental Orthodox body, also felt unfairly underrepresented at the council following the deposition of their Pope, Dioscorus of Alexandria at the council.
The Eastern Orthodox Church accepts seven ecumenical councils, with the disputed Council in Trullo - rejected by Catholics - being incorporated into, and considered as a continuation of, the Third Council of Constantinople.
To be considered ecumenical, Orthodox accept a council that meets the condition that it was accepted by the whole church. That it was called together legally is also an important factor. A case in point is the Third Ecumenical Council, where two groups met as duly called for by the emperor, each claiming to be the legitimate council. The Emperor had called for bishops to assemble in the city of Ephesus. Theodosius did not attend but sent his representative Candidian to preside. However, Cyril managed to open the council over Candidian's insistent demands that the bishops disperse until the delegation from Syria could arrive. Cyril was able to completely control the proceedings, completely neutralizing Candidian, who favored Cyril's antagonist, Nestorius. When the pro-Nestorius Antiochene delegation finally arrived, they decided to convene their own council, over which Candidian presided. The proceedings of both councils were reported to the emperor, who decided ultimately to depose Cyril, Memnon and Nestorius. Nonetheless, the Orthodox accept Cyril's group as being the legitimate council because it maintained the same teaching that the church has always taught.
Paraphrasing a rule by St Vincent of Lérins, Hasler states
...a teaching can only be defined if it has been held to be revealed at all times, everywhere, and by all believers.
Orthodox believe that councils could over-rule or even depose popes. At the Sixth Ecumenical Council, Pope Honorius and Patriarch Sergius were declared heretics. The council anathematized them and declared them tools of the devil and cast them out of the church.
It is their position that, since the Seventh Ecumenical Council, there has been no synod or council of the same scope. Local meetings of hierarchs have been called "pan-Orthodox", but these have invariably been simply meetings of local hierarchs of whatever Eastern Orthodox jurisdictions are party to a specific local matter. From this point of view, there has been no fully "pan-Orthodox" (Ecumenical) council since 787. Unfortunately, the use of the term "pan-Orthodox" is confusing to those not within Eastern Orthodoxy, and it leads to mistaken impressions that these are ersatz ecumenical councils rather than purely local councils to which nearby Orthodox hierarchs, regardless of jurisdiction, are invited.
Others, including 20th century theologians Metropolitan Hierotheos (Vlachos) of Naupactus, Fr. John S. Romanides, and Fr. George Metallinos (all of whom refer repeatedly to the "Eighth and Ninth Ecumenical Councils"), Fr. George Dragas, and the 1848 Encyclical of the Eastern Patriarchs (which refers explicitly to the "Eighth Ecumenical Council" and was signed by the patriarchs of Constantinople, Jerusalem, Antioch, and Alexandria as well as the Holy Synods of the first three), regard other synods beyond the Seventh Ecumenical Council as being ecumenical. 
From the Eastern Orthodox perspective, a council is accepted as being ecumenical if it is accepted by the Eastern Orthodox church at large - clergy, monks and assembly of believers. Teachings from councils that purport to be ecumenical, but which lack this acceptance by the church at large, are, therefore, not considered ecumenical.
Both the Roman Catholic and Eastern Orthodox churches recognize seven councils in the early centuries of the church, but Roman Catholics also recognize fourteen councils in later times called or confirmed by the Pope. At the urging of German King Sigismund, who was to become Holy Roman Emperor in 1433, the Council of Constance was convoked in 1414 by Antipope John XXIII, one of three claimants to the papal throne, and was reconvened in 1415 by the Roman Pope Gregory XII. The Council of Florence is an example of a council accepted as ecumenical in spite of being rejected by the East, as the Councils of Ephesus and Chalcedon are accepted in spite of being rejected respectively by the Church of the East and Oriental Orthodoxy.
The Roman Catholic Church teaches that an ecumenical council is a gathering of the College of Bishops (of which the Bishop of Rome is an essential part) to exercise in a solemn manner its supreme and full power over the whole Church. It holds that "there never is an ecumenical council which is not confirmed or at least recognized as such by Peter's successor". Its present canon law requires that an ecumenical council be convoked and presided over, either personally or through a delegate, by the Pope, who is also to decide the agenda; but the church makes no claim that all past ecumenical councils observed these present rules, declaring only that the Pope's confirmation or at least recognition has always been required, and saying that the version of the Nicene Creed adopted at the First Council of Constantinople (381) was accepted by the Church of Rome only seventy years later, in 451. One writer has even claimed that this council was summoned without the knowledge of the pope.
While the Councils are part of the "historic formularies" of Anglican tradition, it is difficult to locate an explicit reference in Anglicanism to the unconditional acceptance of all Seven Ecumenical Councils. There is little evidence of dogmatic or canonical acceptance beyond the statements of individual Anglican theologians and bishops.
Bishop Chandler Holder Jones, SSC, explains:
We indeed and absolutely believe all Seven Councils are truly ecumenical and catholic - on the basis of the received Tradition of the ancient Undivided Church of East and West. The Anglican formularies address only particular critical theological and disciplinary concerns of the sixteenth and seventeenth centuries, and that certainly by design. Behind them, however, stands the universal authority of the Holy and Apostolic Tradition, which did not have to be rehashed or redebated by Anglican Catholics.
He quotes William Tighe, Associate Professor of History at Muhlenberg College in Allentown, Pennsylvania (another member of the Anglo-Catholic wing of Anglicanism):
...despite the fact that advocates of all sides to the 16th-century religious conflict, Catholic, Lutheran and Reformed alike, were given to claiming that their particular doctrinal stances and, in some cases, distinctive practices, were in accord with those of the Early Church Fathers, or at least with those of high standing (such as St. Augustine), none [but Anglicanism] were willing to require, or even permit, their confessional stances to be judged by, or subordinated to, a hypothetical 'patristic consensus' of the first four or five centuries of Christianity.' But Anglicanism most certainly did, and does so to this day.
Article XXI teaches: "General Councils ... when they be gathered together, forasmuch as they be an assembly of men, whereof all be not governed with the Spirit and word of God, they may err and sometime have erred, even in things pertaining to God. Wherefore things ordained by them as necessary to salvation have neither strength nor authority, unless it may be declared that they be taken out of Holy Scripture."
The 19th Canon of 1571 asserted the authority of the Councils in this manner: "Let preachers take care that they never teach anything...except what is agreeable to the doctrine of the Old and New Testament, and what the Catholic Fathers and ancient Bishops have collected from the same doctrine." This remains the Church of England's teaching on the subject. A modern version of this appeal to catholic consensus is found in the Canon Law of the Church of England and also in the liturgy published in Common Worship:
The Church of England is part of the One, Holy, Catholic, and Apostolic Church, worshipping the one true God, Father, Son, and Holy Spirit. It professes the faith uniquely revealed in the Holy Scriptures and set forth in the catholic creeds, which faith the Church is called upon to proclaim afresh in each generation. Led by the Holy Spirit, it has borne witness to Christian truth in its historic formularies, the Thirty-nine Articles of Religion, The Book of Common Prayer and the Ordering of Bishops, Priests and Deacons.
I, AB, do so affirm, and accordingly declare my belief in the faith which is revealed in the Holy Scriptures and set forth in the catholic creeds and to which the historic formularies of the Church of England bear witness; and in public prayer and administration of the sacraments, I will use only the forms of service which are authorized or allowed by Canon.
Many Protestants (especially those belonging to the magisterial traditions, such as Lutherans, or those such as Methodists, that broke away from the Anglican Communion) accept the teachings of the first seven councils but do not ascribe to the councils themselves the same authority as Roman Catholics and the Eastern Orthodox do. The Lutheran World Federation, in ecumenical dialogues with the Ecumenical Patriarch of Constantinople has affirmed all of the first seven councils as ecumenical and authoritative.
Some, including some fundamentalist Christians, condemn the ecumenical councils for other reasons. Independency or congregationalist polity among Protestants may involve the rejection of any governmental structure or binding authority above local congregations; conformity to the decisions of these councils is therefore considered purely voluntary and the councils are to be considered binding only insofar as those doctrines are derived from the Scriptures. Many of these churches reject the idea that anyone other than the authors of Scripture can directly lead other Christians by original divine authority; after the New Testament, they assert, the doors of revelation were closed and councils can only give advice or guidance, but have no authority. They consider new doctrines not derived from the sealed canon of Scripture to be both impossible and unnecessary whether proposed by church councils or by more recent prophets. Catholic and Orthodox objections to this position point to the fact that the Canon of Scripture itself was fixed by these councils. They conclude that this would lead to a logical inconsistency of a non-authoritative body fixing a supposedly authoritative source.
Ecumenical councils are not recognised by nontrinitarian churches such as The Church of Jesus Christ of Latter-day Saints (and other denominations within the Latter Day Saint movement), Jehovah's Witnesses, Church of God (Seventh-Day), their descendants and Unitarians. They view the ecumenical councils as misguided human attempts to establish doctrine, and as attempts to define dogmas by debate rather than by revelation.
An ecclesiological theory which has been popular since the time of the Slavophile philosopher Alexis Khomiakov first defined it is that ecumenicity--the idea that a particular council is of universal, infallible significance for the Church--is determined by the reception of the whole body of the Church.
So the new teachings, that are outside the ecumenical councils cannot be accepted because they have not been verified (by) the whole body of the Church.