Novus Ordo Missae

The "Novus Ordo Missae" (New Order of the Mass) is the form of the Roman Catholic Mass introduced by Pope Paul VI in 1969, four years after the end of the Second Vatican Council. It replaced the Tridentine Mass or "Traditional Latin Mass", codified by the Council of Trent and promulgated by Pope Pius V in his Papal Bull Quo Primum bull (1570).

The new Roman Missal approved by Pope Paul VI was written by group including six Protestant ministers and led by Archbishop Annibale Bugnini. With the new Mass, the priest now faces the congregation rather than the altar; certain changes to the altar and sanctuary were made; and the new Mass allows, but does not encourage or discourage, the use of vernacular translations (i.e. translations in the local common language). When the vernacular is used, it is still recommended that at least some of the Mass be conducted in Latin and Gregorian chant. The new Roman Missal allows a number of variations and options in the liturgy in comparison with the more rubrical Tridentine Mass. The New Order incorporates some of the text from the older Mass, but a majority of the older prayers have been deleted or modified and new prayers written.

A number of traditional Catholics, believe that the Mass according to the new Roman Missal goes against the bulls of previous popes and contains changes that they would regard as dangerous to the faith. Others link the decline of the Church to the "collapse" of the liturgy and cite abuse of the options allowed in the New Mass throughout the world as the cause of lower Mass attendance and problems in the Catholic Church.

A majority of Catholics attend the Novus Ordo Mass. Pope Paul VI's decree Sacrosanctam Concilium requires the official language of the Mass remains Latin. However, Latin is now rarely used in any church ceremonial.

In the early 2000s it was announced that the Tridentine Mass could once again on occasions be celebrated in St. Peter's Basilica, though not on the main altar. It was separately revealed that Pope John Paul II had begun to celebrate Tridentine Masses in his private oratory in the Apostolic Palace, his official Vatican residence.