Timeline

A petition organised by the Latin Mass Society and presented to Paul VI by Cardinal John Heenan led to a concession, dated 5 November 1971, allowing bishops in England and Wales to authorise Masses with the former Roman Missal for particular groups. It is informally known as the "Agatha Christie indult".

At Archbishop Marcel Lefebvre's request, Bishop François Charrière of Lausanne, Geneva and Fribourg erected the Priestly Society of Saint Pius X as a pious union in his diocese, approving its statutes on a trial basis for six years. According to the Society's published founding documents, the Congregation for the Clergy sent it a letter of praise on 18 February 1971.

In a letter dated 25 September 1969, Cardinals Alfredo Ottaviani and Antonio Bacci sent Paul VI a "Short Critical Study on the New Order of Mass", arguing that the new rite departed from the Catholic theology of the Mass formulated at the Council of Trent's 22nd session. The SSPX still publishes the letter; the Fordham Internet Modern History Sourcebook notes that the opposition did not stop the worldwide change in liturgical practice.

On Holy Thursday 1969, Paul VI issued the apostolic constitution Missale Romanum, promulgating the Roman Missal revised in line with Sacrosanctum Concilium as a revision of the Missal in use since Pius V's edition of 1570. It added three new Eucharistic Prayers and a three-year cycle of Sunday readings, restored elements such as the prayer of the faithful, and took effect on the First Sunday of Advent, 30 November 1969.

On the solemnity of the Immaculate Conception, Paul VI closed the Council at a Mass in St. Peter's Square, with the concluding decree In Spiritu Sancto and messages addressed to rulers, women, workers, artists and young people. The decree directed that everything the Council had established be observed by the faithful.

At the Council's last public session, Paul VI promulgated the Declaration on Religious Freedom alongside the Pastoral Constitution Gaudium et spes. The declaration grounds the right to religious freedom in the dignity of the human person and holds that it should be recognised in civil law; a 2019 International Theological Commission document describes it as real progress in the Church's understanding of relations between Church and state.

Paul VI proclaimed the conciliar declaration Nostra Aetate. Its section 4 teaches that Christ's Passion cannot be charged against all Jews then living or against Jews today, and it decries antisemitism. See Judaism and antisemitism.

Paul VI promulgated the Council's Constitution on the Sacred Liturgy after the bishops approved it by 2,147 votes to 4. Placed at the head of the Council's documents, it presents the liturgy as the summit and source of the Church's life and laid the foundation for the general revision of the liturgical books, including the Roman Missal.

Pope John XXIII opened the Second Vatican Council in St. Peter's Basilica with the address known by its first words, Gaudet Mater Ecclesia, presenting the Council's aim as safeguarding Christian doctrine and teaching it more effectively, and preferring mercy to severe condemnation. The Council went on to meet in four autumn sessions between 1962 and 1965.

In 1960 Plinio Corrêa de Oliveira founded the Brazilian Society for the Defense of Tradition, Family and Property (TFP), drawing on his 1959 book Revolution and Counter-Revolution. Autonomous TFPs followed in other countries, beginning with Argentina, Chile and Uruguay in 1967, according to Wikipedia.

After Leonard Feeney declined repeated summonses to Rome to explain his views, the Holy Office declared him excommunicated in February 1953. Sources give the date as 4 or 13 February. His followers argue that the decree was procedurally defective and contained no doctrinal condemnation.

The Holy Office sent Archbishop Richard Cushing of Boston a letter (Protocol 122/49) on the axiom "outside the Church there is no salvation." It responded to a dispute involving associates of Saint Benedict Center and Leonard Feeney. Excerpts appeared in The Pilot in September 1949, and Cushing published the full text in 1952. The letter was never printed in the Acta Apostolicae Sedis, a point Feeney's followers cite against its authority.