Council of Trent

The Council of Trent (Latin Concilium Tridentinum) was the 19th ecumenical council of the Catholic Church. It met at Trent (Trento) and briefly at Bologna in three periods: 1545–1547, 1551–1552 and 1562–1563, under Popes Paul III, Julius III and Pius IV. It opened on 13 December 1545 and closed on 4 December 1563.

Key decrees

• Scripture and Tradition (Session IV, 1546) declared both to be sources of revelation, fixed the canon, and made the Vulgate authoritative.
• Justification (Session VI, 1547) answered Luther's sola fide.
• The seven sacraments, transubstantiation (Session XIII, 1551), and the Mass as a true propitiatory sacrifice (Session XXII, 1562).
• Reform decrees ordered seminaries for clergy (Session XXIII) and required bishops to reside in their dioceses.
• Also: Purgatory, the veneration of saints and relics, indulgences (Session XXV), and the regulation of marriage (Tametsi).
• The council asked the pope to produce a catechism, missal, breviary and index. Results were the Index of Forbidden Books (1564), the Roman Catechism (1566), the Roman Breviary (1568) and the Roman Missal (1570).

The Tridentine Mass

Pope Pius V promulgated the Roman Missal with the bull Quo primum (14 July 1570). It imposed the missal across the Latin Church, except for rites more than 200 years old. This "Tridentine" Mass remained the norm until the 1969 Missal of Paul VI. It is allowed today under limits: Summorum Pontificum (2007) eased its use, and Traditionis custodes (2021) restricted it.

See Tridentine rite preservation.