The Tridentine Mass, formally known as the Extraordinary Form of the Roman Rite or the Traditional Latin Mass (TLM), is the form of the Mass of the Roman Catholic Church codified by Pope Pius V in 1570 following the Council of Trent (1545-1563). It takes its name from Tridentum, the Latin name for Trent. The rite is celebrated primarily in Latin, with the priest facing the altar rather than the congregation (ad orientem), and follows the rubrics of the 1962 Missal issued under Pope John XXIII - the last edition before the liturgical reforms of the Second Vatican Council introduced the Ordinary Form, commonly called the Novus Ordo, in 1969.

Prior to the Council of Trent, the Roman Church encompassed a range of local liturgical variations. The Council of Trent tasked the papacy with standardizing the rite to address perceived abuses and to establish doctrinal clarity in the context of the Protestant Reformation. The resulting Missal of Pius V (1570) became the normative Mass of the Latin Church for roughly four centuries. Pope John XXIII issued a revised edition in 1962; it is this edition that serves as the basis for the Extraordinary Form as recognized in contemporary Church documents. A fuller account of the development of the rite can be found at Tridentine Mass - History.

The status of the Tridentine Mass within the Catholic Church has been subject to significant regulatory change since the Second Vatican Council. In 1969, Pope Paul VI promulgated the Novus Ordo as the standard form of the Roman Rite. Pope John Paul II and Pope Benedict XVI progressively liberalized access to the older rite, with Benedict's 2007 apostolic letter motu proprio data Summorum Pontificum declaring that the 1962 Missal had never been abrogated and could be celebrated freely by any priest of the Latin Church. Pope Francis substantially reversed this liberalization in 2021 with the apostolic letter Traditionis Custodes, which restricted celebration of the Tridentine Mass to designated locations with explicit episcopal permission and directed that new groups attached to the older rite not be formed. Subsequent clarifications from the Dicastery for Divine Worship have further tightened restrictions in some jurisdictions while implementation has varied considerably by diocese. The practical availability of the Tridentine Mass therefore differs widely depending on geography and the disposition of the local bishop.

The theological and pastoral questions surrounding the two forms - their relationship to each other, their respective validity, and their effects on ecclesial unity - remain subjects of active debate within Catholic theological and canonical circles.

No single authoritative consensus page covers this topic. Liturgical historians broadly agree on the documentary and procedural history of the rite's codification and subsequent revision. Theological and disciplinary questions about the rite's standing, its relationship to the Novus Ordo, and the authority of papal documents restricting or permitting it remain contested. See Tridentine Mass - Liturgical Consensus when available.

Traditional Catholic - Proponents of the Tridentine Mass argue that it more fully expresses the Church's doctrinal tradition, particularly regarding the sacrificial nature of the Mass and the theology of the priesthood, and that its suppression following Vatican II was irregular or illegitimate. See Traditional Catholic Viewpoint.

Reformist Catholic - Supporters of the Novus Ordo and the Second Vatican Council's liturgical program contend that the reformed rite represents a legitimate and needed development, promotes active participation by the laity, and that the older rite's attachment by some communities has become a vehicle for broader dissent from Church authority. See Reformist Catholic Viewpoint.

Hermeneutic of Continuity - A position associated with Benedict XVI and various theologians holds that the two forms of the Roman Rite are not in rupture but represent a continuous tradition, and that both forms can coexist and mutually enrich each other. See Hermeneutic of Continuity Viewpoint.

Ecclesiological / Canonical - Some canonists and ecclesiologists focus on the question of papal authority itself - whether Summorum Pontificum established a right that Traditionis Custodes could validly abrogate, and what the episode reveals about the limits of papal legislative power. See Canonical Debate Viewpoint.

• Tridentine Mass - History
• Tridentine Mass - Debate
• Council of Trent
• Second Vatican Council
• Novus Ordo
• Summorum Pontificum
• Traditionis Custodes
• Catholic Liturgical Reform

1. Pius V, Quo Primum, apostolic constitution, 14 July 1570.
2. John XXIII, Rubricarum Instructum, apostolic constitution, 25 July 1960, reforming the rubrics; the revised Missal incorporating those changes was issued in 1962.
3. Paul VI, Missale Romanum, apostolic constitution, 3 April 1969.
4. John Paul II, Quattuor Abhinc Annos, indult, 3 October 1984; Ecclesia Dei, apostolic letter, 2 July 1988.
5. Benedict XVI, Summorum Pontificum, apostolic letter motu proprio data, 7 July 2007.
6. Francis, Traditionis Custodes, apostolic letter, 16 July 2021.
7. Dicastery for Divine Worship and the Discipline of the Sacraments, Responsa ad Dubia, 4 December 2021.