Q. 1. What is the purpose of Ecumenical Councils?
A. 1. In summary, an Ecumenical Council is a solemn assembly in the Roman Catholic Church, convoked and presided over by the pope and composed of cardinals, bishops, and certain other prelates whose decrees, when confirmed by the pope, become binding. An Ecumenical Council must be convened by the Pope.
The first 7 Councils, up to A.D. 787, are considered ecumenical councils of the Roman Catholic church and the Eastern Orthodox church. The next fourteen councils are considered to be ecumenical of only the Roman Catholic church.
The first 7 Councils were:
First Council of Nicaea, Nicaea - the first ecumenical council in 325 which produced the wording of the Nicene Creed and condemned the heresy of Arianism.
First Council of Constantinople, Constantinople - the second ecumenical council in 381 which added wording about the Holy Spirit to the Nicene Creed.
Council of Ephesus, Ephesus - the third ecumenical council in 431 which declared Mary as mother of God and condemned Pelagius.
Council of Chalcedon, Chalcedon - the fourth ecumenical council in 451 which defined the two natures (human and divine) of Christ.
Second Council of Constantinople, Constantinople - the fifth ecumenical council in 553 which held Origen's writings to be heretic.
Third Council of Constantinople, Constantinople - the sixth ecumenical council in 680-681 which condemned Monothelitism by defining two wills in Christ, divine and human.
Second Council of Nicaea, Nicaea - the seventh ecumenical council in 787 which refuted iconoclasm and regulated the veneration of holy images.
The last 14 Councils were:
Fourth Council of Constantinople - deposed Patriarch Photios I of Constantinople as an usurper and reinstated his predecessor Saint Ignatius. Photius had already been declared deposed by the Pope, an act which the Church of Constantinople accepted at this council. (869-870)
First Council of the Lateran - addressed the investment of bishops and the Holy Roman Emperor's role therein. (1123)
Second Council of the Lateran - reaffirmed Lateran I and addressed clerical discipline (dress, marriages). (1139)
Third Council of the Lateran - restricted papal election to the cardinals, condemned simony, and introduced minimum ages for ordination (thirty for bishops). (1179)
Fourth Council of the Lateran - defined transubstantiation, addressed papal primacy and clerical discipline. (1215)
First Council of Lyon - deposed Emperor Frederick II and instituted a levy to support the Holy Land. (1245)
Second Council of Lyon - attempted reunion with the Eastern churches, approved Franciscan and Dominican orders, a tithe to support crusades, and conclave procedures. (1274)
Council of Vienne - disbanded the Knights Templar. Council of Pisa (1409) attempted to solve the Great Western Schism. (1311–1312)
The council is not numbered because it was not convened by a pope and its outcome was repudiated at Constance.
Council of Constance - resolved the Great Western Schism and condemned John Hus. Also began conciliarism. (1414–1418)
Council of Siena (1423–1424) addressed church reform. Not numbered as it was swiftly disbanded.
Council of Basel, Ferrara and Florence - addressed church reform and reunion with the Eastern Churches, but split into two parties. The fathers remaining at Basel became the apogee of conciliarism. The fathers at Florence achieved union with various Eastern Churches and temporarily with the Eastern Orthodox Church. (1431–1445)
Fifth Council of the Lateran - addressed church reform. (1512–1514)
Council of Trent - addressed church reform and repudiated Protestantism, defined the role and canon of Scripture and the seven sacraments, and strengthened clerical discipline and education. Temporarily attended by Lutheran delegates. (1545–1563, with interruptions)
First Council of the Vatican - defined pope's primacy in church governance and his infallibility, repudiated rationalism, materialism and atheism, addressed revelation, interpretation of scripture and the relationship of faith and reason. (1870; officially, 1870–1960)
Second Council of the Vatican - addressed pastoral and disciplinary issues dealing with the Church and its relation to the modern world, including liturgy and ecumenism. (1962–1965)