The earliest councils of the Church were formal gatherings of the bishops to regulate doctrine or discipline. The Greek sunodos gave us our word ‘synod’ and the Latin equivalent is concilium or word ‘council’. Originally the terms were synonymous. The Council of Nicaea I, describes itself in Greek as a ‘holy synod.’ Gradually the Church began to distinguish between local or provincial councils and ‘general’ or ecumenical councils. The Catholic Church recognizes twenty-one ecumenical councils from Nicea I (325) to the Second Vatican Council (1962-1965). The term ‘ecumenical’ was used by the Church to describe an authoritative and definitive council of the whole Church rather than a local or provincial council or synod. In our modern usage, a ‘council’ is an authoritative gathering of the bishops while a ‘synod’ is merely advisory. In the current code of cannon law it is the prerogative of the Roman Pontiff alone to summon an Ecumenical council and to determine its agenda. All bishops who are members of the college of bishops have the right to a deliberative vote (CIC 338-339). At Vatican II the superior of some men’s religious orders were also given a vote.
Norman Tanner describes ecumenical councils as “the highest peaks of a vast mountain range” (Councils of the Church: A Short History) since the cannons, decrees, creeds and doctrinal statements issued by these councils often repeats those of local synods of bishops and earlier councils. Councils often focused on legislative issues, and the acts of councils issued cannons, decrees and anathemas against certain beliefs. The glossary of the Catechism of the Catholic Church defines an ecumenical council as: “A gathering of all the bishops of the world, in the exercise of their collegial authority over the universal Church. An ecumenical council is usually called by the successor of St. Peter, the Pope, or at least confirmed or accepted by him” (CCC, p. 873)
Quoting from the Second Vatican Council (LG 22), the Catechism notes; "The college of bishops exercises power over the universal Church in a solemn manner in an ecumenical council." But "there never is an ecumenical council which is not confirmed or at least recognized as such by Peter's successor"(CCC 884).
The acts of a duly established and confirmed Ecumenical Council have supreme magisterial authority and are considered infallible when they intend to define dogma. Again quoting Second Vatican Council (LG 25), the Catechism notes;
“The infallibility promised to the Church is also present in the body of bishops when, together with Peter's successor, they exercise the supreme Magisterium," above all in an Ecumenical Council. When the Church through its supreme Magisterium proposes a doctrine "for belief as being divinely revealed," and as the teaching of Christ, the definitions "must be adhered to with the obedience of faith." This infallibility extends as far as the deposit of divine Revelation itself (CCC 891).
The Second Vatican Council is arguably the largest ecumenical council to ever gather in the Church. The Vatican Secretariat of State sent out 2850 invitations (85 Cardinals, 8 Patriarchs, 533 archbishops, 2131 bishops, 26 abbots, 68 superiors-general of religious orders of men). All but a few hundred who were impeded by ill health or hostile communist governments attended. 2860 prelates attended in part over the four years. From start to finish 253 fathers died and 296 were added during the council. There were bishops from 116 counties represented. Fr. John O’Malley S.J. notes that “Pope John XXIII launched a process that would culminate in what was quite possibly the largest biggest meeting in the history of the world” (What Happened at Vatican II, p. 18). O’Malley notes the following geographic distributions of the prelates:
• 36% Europe
• 34% The Americas
• 20% Asia and Oceania
• 10% Africa
• The US with 7% of the world’s Catholic had 12% of the bishops
There were more bishops from more parts of the world than had ever gathered before in the history of the Church.
Following the leadership of Pope John XXIII, the fathers of the Second Vatican Council deliberately chose a different style than previous councils. They issued no cannons or anathemas. They deliberately chose the style of encouragement and persuasion (O’Malley calls the style ars laudandi, or panegyric) using theological argument, quotes from Sacred Scripture and the Fathers to guide the Church. The goal was to be evangelistic and to dialogue with the modern world.
The council issued sixteen ‘decrees’ but used varying terminology to grade the status of the council documents from higher to lower authority. The most solemn four were called ‘constitutions,’ next were nine ‘decrees’ and finally three were termed ‘declarations.’ The 1985 Extraordinary Synod of bishops affirmed again that “The four constitutions of the council (those on liturgy, church, revelation and church in the modern world) are the hermeneutical key to the other documents—namely, the council’s nine decrees and three declarations.” (as summarized by Cardinal Dulles America Magazine, 2/24/2003) The constitutions were the central foundational documents of the council, and among these documents two were given the added the adjective ‘dogmatic’ and one the adjective ‘pastoral.’ The adjective “pastoral” indicates the pastoral application to the world and not that this document less authoritative.