Timeline: The Latin Mass movement

The motu proprio declared the reformed liturgical books "the unique expression of the lex orandi of the Roman Rite", made the 1962 Missal subject to the diocesan bishop's authorisation, barred new groups, and abrogated earlier norms not in conformity. Francis's accompanying letter cited a 2020 consultation of bishops.

Benedict XVI permitted the 1962 Missal as an extraordinary form of the Roman Rite, effective 14 September 2007. His accompanying letter said the older Missal had never been juridically abrogated and described the two Missals as two uses of one rite.

On 19 April 2005, the second day of the conclave, the cardinal electors chose Cardinal Joseph Ratzinger, 78, prefect of the Congregation for the Doctrine of the Faith since 1981, as the 265th pope; Religion News Service reported that he was elected on the fourth ballot. He later said he chose the name Benedict to link his pontificate to Benedict XV and to the cause of peace and reconciliation.

Two days after Archbishop Marcel Lefebvre's unlawful episcopal ordinations of 30 June, John Paul II's motu proprio stated that excommunication had been incurred, created the Pontifical Commission Ecclesia Dei, and asked for a "wide and generous application" of the permissions for the 1962 Missal.

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.