Each was called because a question had become urgent. The rejected position is stated as fairly as the accepted one, because the people who held it were usually trying to protect something real.
First Council of Nicaea
325Nicaea, in modern Turkey
The question: Is the Son fully God, or the first and highest of created things?
Decided: The Son is of one essence with the Father, begotten and not made. The first form of the Nicene Creed.
Rejected: Arianism, which held that the Son was created by the Father before time and was therefore not eternal in the same sense. Arius was not a fool or a cynic; his concern was to protect the oneness of God, and his position was popular enough to dominate for decades after the council.
Received by: All traditions.
First Council of Constantinople
381Constantinople
The question: Is the Holy Spirit fully God?
Decided: The Spirit is Lord and giver of life, worshipped and glorified with the Father and the Son. The creed reached the form most churches recite.
Rejected: The view that the Spirit was a created power rather than fully divine.
Received by: All traditions.
The Council of Ephesus
431Ephesus
The question: Is Mary rightly called Theotokos, God-bearer?
Decided: Yes, because the one she bore is one person who is God. The title is a statement about Christ before it is a statement about Mary.
Rejected: Nestorianism, understood as dividing Christ into two persons. Whether Nestorius actually taught what was condemned is still argued by historians.
Received by: Catholic, Orthodox, and most Protestant churches. The Assyrian Church of the East does not receive it.
The Council of Chalcedon
451Chalcedon
The question: How are the divine and human natures related in one Christ?
Decided: Two natures in one person, without confusion, change, division, or separation.
Rejected: Eutychianism, which held that the human nature was absorbed into the divine so that Christ had one nature after the union.
Received by: Catholic, Orthodox, and most Protestant churches. The Oriental Orthodox churches, including the Coptic, Armenian, and Ethiopian, did not accept the wording, and modern dialogue has concluded the difference is largely terminological.
Second Council of Nicaea
787Nicaea
The question: May Christians make and venerate images?
Decided: Yes. Images may be venerated, with honor passing to the one represented, while worship belongs to God alone.
Rejected: Iconoclasm, which held that images inevitably become idols.
Received by: Catholic and Orthodox churches. Most Protestants do not treat it as binding, and Reformed traditions in particular kept the iconoclast concern.
The Council of Trent
1545 to 1563Trent, in northern Italy
The question: How should the Catholic Church answer the Reformation?
Decided: Defined justification, the seven sacraments, and the canon including the deuterocanonical books, and reformed a range of clerical abuses.
Rejected: The Reformation formulations of justification by faith alone and Scripture alone.
Received by: Catholic. Protestants regard it as the point at which the division was formalized.
Second Council of Vatican
1962 to 1965Rome
The question: How does the Catholic Church relate to the modern world and to other Christians?
Decided: Liturgy in the vernacular, a renewed emphasis on Scripture, and a markedly warmer stance toward other Christians and other faiths.
Rejected: No new condemnations of doctrine; it was a pastoral council rather than a defining one.
Received by: Catholic. Widely noted by other traditions as the change that made much modern ecumenical conversation possible.