The ecumenical councils were a series of gatherings of church leaders and theologians in the history of Christianity aimed at defining doctrine and settling controversies within the church. The word “ecumenical” comes from the Greek word oikoumene, meaning “worldwide” or “universal”, indicating the intention of these councils to represent the universal church.
There have been 21 ecumenical councils recognized by the Catholic Church, while the Eastern Orthodox Church recognizes the first seven. Protestants generally accept the teachings only of the first four councils. The first ecumenical council is considered to be the First Council of Nicaea in 325 AD, convened by Roman Emperor Constantine I in response to the Arian controversy over the divine nature of Jesus Christ. Subsequent councils continued to debate Christological issues and clarify orthodox Christian doctrine on the Trinity and the nature of Christ.
Here is an overview of the major ecumenical councils, their key decisions and significance:
First Council of Nicaea (325 AD)
The First Council of Nicaea was convened by Emperor Constantine to resolve the Arian controversy initiated by Arius, a presbyter in Alexandria who taught that Jesus was not divine but a created being. The council condemned Arianism and affirmed that Jesus is in fact God, eternally begotten from the Father and of one substance (homoousios) with the Father, resolving a critical Christological debate at the time. The council also issued the original version of the Nicene Creed, an important statement of orthodox Christian doctrine still used in many churches today.
First Council of Constantinople (381 AD)
The First Council of Constantinople was called by Emperor Theodosius to resolve continuing debates, particularly relating to Arianism and Trinitarian theology. This council affirmed the divinity of the Holy Spirit as equal to the Father and Son, opposing views that considered the Spirit inferior. The Nicene Creed was expanded to its current form, which clearly defined the Trinity – Father, Son and Holy Spirit as three persons of one Godhead.
Council of Ephesus (431 AD)
The Council of Ephesus addressed the Nestorian heresy, initiated by Patriarch Nestorius of Constantinople who proposed that Christ existed as two separate natures and denied Mary the title of Theotokos (God-bearer). The council condemned Nestorianism, affirmed that Christ existed as one person with two natures united in one hypostasis, and upheld the title of Mary as Mother of God. The council also affirmed the Nicene Creed.
Council of Chalcedon (451 AD)
The Council of Chalcedon dealt with the Eutychian or Monophysite controversy that denied the human nature of Christ, proposing that he only had a divine nature. The council affirmed that Christ has two natures – fully human and fully divine – united in one hypostasis without confusion, change or division. The council issued the Chalcedonian Definition, an important statement affirming orthodox Christology.
Second Council of Constantinople (553 AD)
The Second Council of Constantinople was convened by Emperor Justinian I to decide matters of certain church controversies including Nestorianism, Eutychianism and Origenism. The council condemned certain teachings associated with these views and affirmed the canons and decrees of the previous four councils as having ecumenical authority.
Third Council of Constantinople (680-681 AD)
The Third Council of Constantinople affirmed that Christ possessed two wills and two natural operations – divine and human. It condemned monothelitism, the view that Christ had only a divine will and no human will. The council also addressed the issue of images in churches, affirming their validity and use in worship while opposing their idolatrous worship.
Second Council of Nicaea (787 AD)
The Second Council of Nicaea was called by the Byzantine Empress Irene to resolve the iconoclastic controversy, a dispute over the use of religious images and icons. The council determined that icons could be revered but not worshiped as divine. It affirmed the validity of honoring icons, relics, and sacred images, restoring their use in churches after the iconoclastic period.
These first seven councils are recognized by both Catholic and Eastern Orthodox churches. The following councils are recognized as ecumenical only by the Catholic Church.
Fourth Council of Constantinople (869-870 AD)
The Fourth Council of Constantinople addressed issues relating to Photian Schism involving the deposition of Patriarch Ignatius of Constantinople and the succession of Photius. The council condemned Photius and affirmed Ignatius as the rightful patriarch, resolving a dispute over papal authority in eastern and western churches.
First Council of the Lateran (1123 AD)
The First Lateran Council was called by Pope Callistus II to confirm Concordat of Worms ending the Investiture Controversy over the right of secular rulers to appoint bishops. The council affirmed ecclesiastical freedom and condemned lay investiture. It also mandated clergy celibacy and opposed simony and nepotism of ecclesiastics.
Second Council of the Lateran (1139 AD)
The Second Lateran Council sought to ensure the unity of the church and strengthen papal authority by ruling on disciplinary matters such as clergy discipline, clerical dress, teaching of theology and administration of sacraments. The council also ruled it unlawful for clergy to bear arms or take lives.
Third Council of the Lateran (1179 AD)
The Third Lateran Council enacted disciplinary reforms on clergy, including education requirements and residence. The council also mandated a two-thirds majority of cardinals to elect a pope. Additionally, it ruled on issues of heresy, supporting the use of force to combat heterodox movements and doctrines opposed to the church.
Fourth Council of the Lateran (1215 AD)
The Fourth Lateran Council mandated the Inquisition process for dealing with heresy. It defined transubstantiation, the miraculous change of bread and wine into the body and blood of Christ during the Mass. The council also required Jews and Muslims to wear special clothing to distinguish themselves from Christians.
First Council of Lyon (1245 AD)
The First Council of Lyon was convened to continue Dialogue between the Western (Catholic) and Eastern (Orthodox) churches towards potential reunification. While a reunion was briefly achieved and Byzantine Emperor Michael Palaeologus accepted the Catholic Church, the reunification was short-lived. Longstanding theological and political differences remained unresolved.
Second Council of Lyon (1274 AD)
The Second Council of Lyon was convened by Pope Gregory X largely to enact reforms on the clergy, including upholding clerical discipline, education requirements and residency. Like the previous council, attempts were made at east-west reunification but the various differences between the churches remained too great.
Council of Vienne (1311-1312 AD)
The Council of Vienne was called by Pope Clement V primarily to address the Order of the Knights Templar, ultimately deciding to dissolve the Templars on grounds of heresy and immorality. The council also addressed issues of financing another potential crusade to the Holy Land.
Council of Constance (1414-1418 AD)
The Council of Constance was convened to resolve the Great Western Schism during which there were two or three competing popes at the same time. The council elected Pope Martin V, bringing an end to the schism. It also condemned the teachings of John Wycliffe and Jan Hus who were viewed as forerunners of the Protestant Reformation.
Council of Florence (1431-1445 AD)
The Council of Florence was another attempt to foster dialogue between the Catholic and Eastern Orthodox churches towards potential unification. After a short-lived east-west union, major doctrinal, liturgical and political differences again proved too great to achieve lasting resolution.
Fifth Council of the Lateran (1512-1517 AD)
The Fifth Council of the Lateran focused on disciplinary reforms of the clergy. It affirmed the doctrine of the immortality of the soul and legislated the censorship of books. The council condemned the errors of the church reformer Martin Luther after he posted his 95 Theses which began the Protestant Reformation.
Council of Trent (1545-1563 AD)
The Council of Trent was the Catholic Church’s response to the Protestant Reformation. It affirmed central Catholic doctrines questioned by reformers such as transubstantiation, the authoritative role of tradition, efficacy of sacraments and the authority of the Vulgate Bible. It also enacted far-reaching reforms on clergy discipline and church administration.
First Vatican Council (1869-1870 AD)
The First Vatican Council established the doctrine of papal infallibility, affirming that the Pope is infallible when defining a doctrine concerning faith or morals. It also affirmed traditional Catholic teachings such as the existence of miracles and the real presence of Christ in the Eucharist.
Second Vatican Council (1962-1965 AD)
The Second Vatican Council instituted major reforms in the Catholic Church to modernize practices and affirm relations with other Christian denominations and other religions. Changes included the introduction of vernacular languages into the liturgy. The council presented the Church’s teachings in ways more relevant to the modern world.
In summary, the ecumenical councils played a vital role in shaping Christian theology and doctrine over the centuries. While not without conflict and controversy, they ultimately helped unify belief, clarify contested issues, and adapt the faith to changing times and cultures.