The Church held councils to resolve issues when less formal dialogue failed to produce a consensus. Most councils were local, although in some cases their decrees gained wide acceptance (such as the Seven Ecumenical Councils). The first council of the Church was held by the Apostles in Jerusalem during the first century (refer to Acts 6:1-7).

The seven General Councils of the entire Christian Church are known as the Ecumenical Councils. They cover the period between 325-757 AD and their decisions are at the foundation of Christian doctrine accepted by both the Eastern and Western segments of the Christian Church. The decisions of these Ecumenical Councils were made under the guidance of the Holy Spirit, as promised by Jesus Christ to His Apostles.

At these Ecumenical Councils many Canons, or laws governing the administration of the Church, were composed. A detailed listing of all of these Canons is available

The Western Church accepts subsequent Councils as Ecumenical, that were convened and attended only by the authorities and delegates of the Roman Church. These Councils, the last of which is the second Vatican Council (1962-1965), are not accepted by the Orthodox Church as bearing either the validity or the authority that the seven truly Ecumenical Councils possessed; and for that matter; no decisions of these Roman Catholic Councils have any bearing on the Orthodox Church. For better appreciating the reasons for being convened and the decisions reached, all seven Ecumenical Councils are presented in sequence rather than in alphabetical order.

First Ecumenical Council

The First Ecumenical Council was summoned by Emperor Constantine the Great in 325, May 20th. The Council assembled at Niceea in the province of Bithynia of Asia Minor and was formally opened by Constantine himself. The Council passed 20 canons including the Nicene Creed (described below), the Canon of Holy Scripture (Holy Bible), and established the celebration of Pascha (Easter).

The main reason for its being called was the Arian controversy. Arius, a presbyter (priest) from Alexandria, held that Jesus Christ was created by God and denying Christ's divinity. Arius argued that if Jesus was born, then there was time when He did not exist; and if He became God, then there was time when He was not. Arius' original intent was to attack another heretical teaching by which the three persons of the Godhead were confused (Sabellianism).

A number of bishops followed Arius, and the Church went into her first and perhaps deepest division of faith. Up to then, statements of faith were incorporated into Creeds recited by a candidate to Baptism. A baptismal Creed representing Arianism was submitted to the Council by Eusebios of Nicomedia but was at once rejected. Another Creed, representing the baptismal Creed of Jerusalem, was finally accepted with the addition of the very important term 'homoousios', meaning of the 'same substance'. Thus, the view that Christ was of the 'same substance' with the Father was received as orthodox. This Creed is known as the Nicene Creed, which read:

We (I) believe in one God. The Father Almighty. Maker of heaven and earth, and of all things visible and invisible.
And in one Lord Jesus Christ, the Son of God, the only begotten, begotten of the Father before all ages. Light of Light; true God of true God; begotten not made; of one essence with the Father, by whom all things were made.
Who for us men and for our salvation came down from heaven, and was incarnate of the Holy Spirit and the Virgin Mary, and became man.
And He was crucified for us under Pontius Pilate, and suffered, and was buried.
And the third day He rose again according to the Scriptures.
And ascended into heaven, and sits at the right hand of the Father; and he shall come again with glory to judge the living and the dead; whose Kingdom shall have no end.

Second Ecumenical Council

The Second Ecumenical Council was convened by Emperor Theodosius I at Constantinople in 381, which was attended by 150 bishops. Theodosius proved to be a champion of the orthodox faith, and his intent in calling this Council was to completely eradicate Arianism, and condemn Macedonios and Apollinarianism, by establishing the teaching on the unity of the Holy Trinity and the complete manhood in Christ.

Macedonius taught that the Holy Spirit was not a person ('hypostasis'), but simply a power ('dynamic') of God. Therefore concluding that the Holy Spirit was inferior to the Father and the Son. The Council condemned Macedonius' teaching and defined the doctrine of the Holy Trinity. This doctrine decrees that there is 'one God in three hypostases'; proclaiming that the Holy Spirit is fully God, equal to the Father and the Son, and of one essence with them. This became the base of the Christian faith.

The Nicene Creed, received by the First Ecumenical Council, was then supplemented with five canons setting forth doctrines on the Holy Spirit, the Church, the Sacraments, resurrection of the dead and life of the age to come: which read:

And (We believe) in the Holy Spirit, the Lord, the Giver of Life, who proceeds from the Father, Who with the Father and the Son together is worshipped and glorified; Who spoke by the Prophets.
In One Holy, Catholic, and Apostolic Church.
I acknowledge One Baptism for the remission of sins.
I look for the resurrection of the dead, and the life of the world to come. Amen.

The third Council was convened at Ephesus in 431 by Emperor Theodosius. The Council condemned the doctrines of Nestorios, Archbishop of Constantinople, who taught that there were two separate persons in the Incarnate Christ, the one Divine and the other Human.

Nestorios over-emphasising the human nature of Christ at the expense of the divine, teaching that the Virgin Mary gave birth to a man (Jesus Christ), and not God (the 'Logos' and Son of God). The Logos (or 'Word') only dwelled in Christ, as in a Temple. Christ, therefore, was only the Theophoros or the 'Bearer of God'. This was directly opposite to the orthodox doctrine by which the Incarnate Christ was a single Person, at once God and Man.

One of the high points of Nestorios' teaching was the rejection of the name 'Theotokos' (bearer of God) for the Virgin Mary. Nestorios called the Virgin Mary Christotokos (bearer of Christ) rather than Theotokos. Hence, giving the name to the 'Christological controversies'.

The Council reiterated the Church's teaching that Our Lord Jesus Christ is one person, not two separate 'people'. The Council decreed that Lord Jesus Christ, the Son of God (Logos), is perfect God and perfect Man with a rational soul and body. The union of the two natures of Christ took place in such a fashion that one did not disturb the other. The Council established the name 'Theotokos' in the liturgical and theological usage of the Church, and affirmed the Nicene-Constantionopolitan Creed forbidding any addition or deletion to it.

Two hundred bishops attended this Council among whom St. Cyril of Alexandria who proved to be the orthodox champion and the force behind the condemnation and anathematising of Nestorios.

Fourth Ecumenical Council

This Council was convened at Chalcedon, on the Asian side of Constantinople, by Emperor Marcian and his wife Poulcheria in 451. It had to deal with another controversy about the Person of Christ. Eutyches, an Archimandrite in Constantinople, held that the human (less perfect) nature of Christ had been completely absorbed by His divine nature and thus the two had been confounded into one. Thus, after this union, Eutyches held, there was only one nature in Christ. Hence his heresy was called 'monophysitisim' (of one nature). The Council condemned this teaching and affirmed that there were two perfect natures in the one Person of Christ unified 'unconfusedly, unchangeably, indivisibly, and inseparably'.

The Council was attended by 650 bishops. The dogmatic decisions of this Council were expressed by a statement of faith since then called the Chalcedonian Definition. Among other important enactments there was one that the Western Church did not accept: canon 28 by which the Archbishop of Constantinople was given the title of Patriarch thus reiterating the decision of the Second Ecumenical Council by which the Bishop of Constantinople was given honourary precedence over all other Churches, save that of Rome. Canon 28 of this Council further recognised to the Archbishop of Constantinople extensive administrative rights over a number of provinces around Constantinople and thus made him a Patriarch. This was rejected in the West on the excuse 'that the interests of the older Eastern Patriarchates should be protected'.

  Fifth Ecumenical Council

The Fifth Ecumenical Council met in Constantinople in 553 and was convoked by Emperor Justinian I. The Monophysite controversy continued unabated even after the condemnation of Eutyches and the issuing of the Chalcedonian Statement of Faith.

Personal quarrels among bishops and the interference of the palace in theological and ecclesiastical matters helped to create an unfortunate situation in the Church that even Justinian's great authority and influence failed to correct.

Justinian favoured at first the Monophysites but later sided with the formal Orthodox view against it. However, empress Theodora encouraged the Monophysites to create new problems by stirring up a new controversy regarding the theological positions of three distinguished theologians already dead for a century, these were the three Antiochian bishops and renowned teachers, Theodore of Mopsuestia, Theodoret of Cyrus, and Ibas of Edessa. The accusation was that the writings of all three, tainted with Nestorianism, had been condemned by the Third Ecumenical Council .

The Monophysite-accusers wished all three to be condemned even though they were dead. Justinian was compelled by the fury of the controversy to call this Fifth Ecumenical Council in Constantinople which opened on May 5, 553 and was presided over by the Patriarch of Constantinople Eutychios.
One hundred sixty five bishops attended, and the writings of the three famous teachers were condemned and they themselves were anathematised. This decision was not easily accepted in the West. During the Council a quarrel erupted between Eastern and Western bishops as to anathematising the dead, and for a time the name of the Pope was erased from the diptychs. But as a result of Justinian's efforts, a permanent rupture between East and West was prevented.

The Council confirmed the Church's teaching on the dual nature of Christ, and reaffirmed that He is both Truly God and Truly Man. Emperor Justinian himself confessed his Orthodox faith in a form of the famous Church hymn "Only begotten Son and Word of God" which is sung during the Divine Liturgy.

Sixth Ecumenical Council

The Sixth Ecumenical Council met in Constantinople in 680 and was convened by Emperor Constantine IV (Pogonatos) and was attended by 170 bishops.

Monothelitism (one will), in spite of the decisions of the Fifth Ecumenical Council and in spite of the strict laws and other repressive measures against it by subsequent emperors, continued to be a serious disturbance to both Church and State. It actually was used as the foundation for the creation of new and independent Churches such as the Armenian, Abyssinian, and others.

As a result of the reconciliatory endeavours of Emperor Herakleios for the purpose of bringing back the Armenians to the Orthodox Church, a new teaching in regard to the Person of Christ began to spread. By it, there is only one will in the God-man Christ. Hence this teaching was called 'monothelitism' and was originally proposed as a midpoint between Monothelitism and Orthodoxy designed to bring back the Monophysites at a time the Byzantine empire was threatened by the Persians and later by the Mohammedans.

Both the Patriarch of Constantinople Sergios and Pope Honorius accepted the Emperor's formula by which there were two natures in Christ but only one mode of 'activity'. But in a statement of doctrine, the Pope used the unfortunate expression 'of one will' in Christ which from that point on replaced the expedient 'one energy' agreed upon by both parties.

After some tumultuous developments, the monotheletic controversy was finally resolved by the Sixth Ecumenical Council. Monothelitism was condemned together with its adherents.

The Council proclaimed that "Christ had two natures with two activities: as God working miracles, rising from the dead and ascending into heaven; as Man, performing the ordinary acts of daily life. Each nature exercises its own free will". Christ's divine nature had a specific task to perform and so did His human, without being confused nor subjected to any change or working against each other. "The two distinct natures and related to them activities were mystically united in the one Divine Person of our Lord and Saviour Jesus Christ".

The Quinisext or Trullan Council

This is not the Seventh Ecumenical Council but rather a supplement to the Fifth and Sixth Ecumenical Councils. It met in Constantinople in the hall under the great dome (Trullos) of the Imperial Palace. Hence it is known as the Trullan Synod while in Greek it is known as the 5th-6th where from the Latin Quinisext came.

The Council was called by Justinian II in 692. Both the Fifth and Sixth Ecumenical Councils fully occupied their time with the Christological problem and issued no canons pertaining to ecclesiastical government and order. Actually, the Quinisext may be considered to be the continuation of all the preceding Ecumenical Councils inasmuch as by its 2nd canon it received and ratified all of their canons and decisions. It also ratified the so-called "Eighty-five Apostolic Canons", the canons of local synods, and the most important of the canons of the principal Fathers of the Church, thus empowering all of them with Ecumenical authority.

The disciplinary canons of the Quinisext, however, were not accepted by the Pope, and even though most of them were not completely observed in the East, they contributed appreciably to the widening of differences between East and West. For example, canons 13, 30, and 48 relating to the marital status of the clergy, others regulating the age of ordination, and still others relating to canonical impediments to matrimony, were contrary to already established different practices in the West that the Roman See did not wish to change on directives from the Quinisext Council. However, the same Council tabulated by its 6th canon a shaky practice in the East by which marriage could not be contracted after one had been ordained in any one of the three ranks of priesthood. Thus, and for the first time, priesthood as a sacrament was accorded precedence and superiority over the sacrament of matrimony. And though there is no dogmatical justification for this doctrinal demoting of the sacrament of matrimony, the prohibition of marriage after ordination continues in the Orthodox Church to this day.

Seventh Ecumenical Council

This Council dealt predominantly with the controversy regarding icons and their place in Orthodox worship. It was convened in Niceea in 787 by Empress Irene at the request of Thrasios, Patriarch of Constantinople. The Council was attended by 367 bishops.

Almost a century before this, the iconoclastic controversy had once more shaken the foundations of both Church and State in the Byzantine empire. Excessive religious respect and the ascribed miracles to icons by some members of society, approached the point of worship (due only to God) and idolatry. This instigated excesses at the other extreme by which icons were completely taken out of the liturgical life of the Church by the Iconoclasts. The Iconophilles, on the other-hand, believed that icons served to preserve the doctrinal teachings of the Church; they considered icons to be man's dynamic way of expressing the divine through art and beauty.

The Council decided on a doctrine by which icons should be venerated but not worshipped. In answering the Empress' invitation to the Council, Pope Hadrian replied with a letter in which he also held the position of extending veneration to icons but not worship, the last befitting only God.

The decree of the Council for restoring icons to churches added an important clause which still stands at the foundation of the rationale for using and venerating icons in the Orthodox Church to this very day: "We define that the holy icons, whether in colour, mosaic, or some other material, should be exhibited in the holy churches of God, on the sacred vessels and liturgical vestments, on the walls, furnishings, and in houses and along the roads, namely the icons of our Lord God and Saviour Jesus Christ, that of our Lady the Theotokos, those of the venerable angels and those of all saintly people. Whenever these representations are contemplated, they will cause those who look at them to commemorate and love their prototype. We define also that they should be kissed and that they are an object of veneration and honour (timitiki proskynisis), but not of real worship (latreia), which is reserved for Him Who is the subject of our faith and is proper for the divine nature. The veneration accorded to an icon is in effect transmitted to the prototype; he who venerates the icon, venerated in it the reality for which it stands".

The Council issued also 22 canons relating to administrative and disciplinary matters, condemning Simony (ordination for payment), the election of bishops by secular authority, and the erecting of mixed monasteries. However, and in spite of the recognition of this Council by the Pope, Charlemagne refused to recognise it not only as Ecumenical but altogether. He disapproved of its decision for venerating the icons, and as a result of his hostility, a synod at Frankfurt in 794 condemned the veneration of icons and rejected the entire Council. And it was only by the end of the 9th century that the Council was recognised in the West but without its rules that were contrary to the established practices of the Roman Church.

An Endemousa (Regional) Synod was called in Constantinople in 843. Under Empress Theodora. The veneration of icons was solemnly proclaimed at the St. Sophia's Cathedral. Monks and clergy came in procession and restored the icons in their rightful place. The day was called "Triumph of Orthodoxy." Since that time, this event is commemorated yearly with a special service on the first Sunday of Lent, the "Sunday of Orthodoxy".