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Council of Trent and the Catholic Reformation
1545–1563· Council, creed or writing· Church, doctrine & the world
Historical recordConfirmed by archaeology, outside sources or contemporary records.
The Catholic council of 1545–1563 that answered Protestantism, defined doctrine and reformed the clergy, shaping Catholicism for 400 years.
See it on the Bible & Christianity map →What it is
Pope Paul III opened it at Trent, in northern Italy, in December 1545; it met in three periods over 18 years. On doctrine it affirmed Scripture and Tradition together, a 73-book Bible, seven sacraments, transubstantiation, and justification by grace that works through faith and good works. On discipline it required bishops to live in their dioceses, abolished professional indulgence sellers and ordered a seminary for every diocese. It produced the Roman Catechism (1566) and the Latin 'Tridentine' Mass (1570).
Why it matters
It drew a clear line between Catholic and Protestant teaching and set Catholic worship and priestly training until the Second Vatican Council (1962–1965).
Sources and history
Its decrees and canons were published in 1564; the secretary Angelo Massarelli kept detailed diaries, and delegates' letters, speeches and votes survive in the Vatican archives.
Questions and debates
Historians debate 'Counter-Reformation' (a reaction) versus 'Catholic Reformation' (a reform already under way); most now use both. Only about 30 bishops attended the opening.
Inside this (1)
Connections (7)
▸The biblical canon: the agreed list of books was formally fixed for Catholics at Council of Trent and the Catholic ReformationHistorical record
The connection
Protestants had moved seven Old Testament books, such as Tobit and 1–2 Maccabees, out of their Bibles' main text as 'Apocrypha'. Trent answered on April 8, 1546, listing all 73 books as fully Scripture and condemning anyone who rejected them. Earlier councils (Hippo 393, Carthage 397, Florence 1442) had listed the same books, but Trent made the list binding dogma.
When and where
Trent, northern Italy, at the council's fourth session, April 8, 1546, in the decree 'On the Canonical Scriptures'.
Historical evidence
The decree's text survives and names each book; Luther's 1534 Bible, which grouped the same books as 'Apocrypha', shows what it was answering.
Questions and debates
Orthodox churches accept a few more books (such as 3 Maccabees); Protestants follow the shorter Hebrew canon. Which canon the earliest church used is still debated.
▸Thomas Aquinas and the Summa Theologiae shaped the theology of Council of Trent and the Catholic ReformationHistorical record
The connection
Aquinas's Summa Theologiae (1265–1274) supplied much of the framework and vocabulary Trent used, notably his account of transubstantiation and his reasoning on grace, merit and the sacraments. Many theologians at Trent, especially Dominicans, were trained on Aquinas, and in 1567 Pope Pius V declared him a Doctor of the Church.
When and where
Trent, 1545–1563, nearly three centuries after Aquinas died; his Dominican order and Jesuit theologians carried his thought into the debates.
Historical evidence
Trent's decrees on justification and the Eucharist closely follow Aquinas's distinctions and terms, and delegates' working papers cite him often.
Questions and debates
The story that the Summa lay on the altar beside the Bible at Trent, repeated by Pope Leo XIII in 1879, is doubted by historians.
▸The sacraments (baptism, Eucharist and the seven) were defined as seven by Council of Trent and the Catholic ReformationHistorical record
The connection
Protestant reformers kept only two sacraments, baptism and the Lord's Supper, as instituted by Christ in Scripture. Trent declared there are exactly seven, all instituted by Christ: baptism, confirmation, Eucharist, penance, anointing of the sick, holy orders and marriage. It taught that they convey grace through the rite itself (ex opere operato) and affirmed transubstantiation (1551).
When and where
Trent's seventh session, March 3, 1547, defined the seven; later sessions covered the Eucharist and penance (1551), the Mass (1562) and marriage (1563).
Historical evidence
Trent's canons survive, each condemning a specific Protestant view; the number seven had already been listed by Peter Lombard (about 1150) and the Council of Florence (1439).
Questions and debates
The Orthodox also count seven 'mysteries' but never fixed the number so strictly; Anglicans and Lutherans differ on whether confession and other rites are sacraments.
▸Council of Trent and the Catholic Reformation answered The Protestant ReformationHistorical record
The connection
Trent was the Catholic Church's formal reply to Luther, Zwingli and Calvin. Point by point it rejected Protestant teachings and condemned them, while also fixing abuses Protestants had attacked, such as absentee bishops, poorly trained priests and indulgence peddling. In doing so it hardened the division into separate Catholic and Protestant churches.
When and where
Trent, northern Italy, 1545–1563; Protestants were invited to the middle period (1551–1552), and a few envoys came, but no agreement followed.
Historical evidence
Trent's canons name the views they condemn, often closely; Protestant replies, such as Martin Chemnitz's Examination of the Council of Trent (1565–1573), answer them directly.
Questions and debates
Whether an earlier council, before positions hardened (Luther appealed for one in 1520), could have prevented the split remains a classic 'what if'.
▸Ignatius of Loyola and the Jesuits carried out the reforms of Council of Trent and the Catholic ReformationHistorical record
The connection
Two of Ignatius's first companions, Diego Laínez and Alfonso Salmerón, served at Trent as papal theologians. Afterward the Jesuits put its program into practice: they opened colleges and seminaries, preached, heard confessions, wrote catechisms (Peter Canisius's of 1555 ran to some 200 editions in his lifetime) and won back parts of Poland, Austria and southern Germany for Catholicism.
When and where
Trent, 1546–1563, for Laínez and Salmerón; then across Catholic Europe, where by 1600 the Jesuits ran hundreds of schools.
Historical evidence
Council records list the Jesuit theologians and their speeches; Jesuit college foundation records and catechism print runs document the follow-through.
Questions and debates
Historians debate how much the Catholic revival was driven from Rome and by orders like the Jesuits, versus by local bishops, rulers and lay believers.
▸Council of Trent and the Catholic Reformation rejected Faith alone, Scripture alone (Reformation principles)Historical record
The connection
Luther taught that sinners are justified, made right with God, by faith alone, with Scripture alone as final authority. Trent's decree on justification (1547) taught that God's grace begins justification but that believers cooperate and grow in it through faith, hope, love and good works; its fourth session (1546) placed Scripture and church Tradition together.
When and where
Trent, sixth session, January 13, 1547, after seven months of debate; the decree has 16 chapters and 33 canons.
Historical evidence
The decree survives, including canon 9 condemning 'faith alone' as the council understood Protestants to teach it, alongside the Luther writings it answers.
Questions and debates
In 1999 Catholics and Lutherans signed a Joint Declaration saying their teachings on justification no longer warrant mutual condemnation; how deep that agreement goes is still debated.
▸Council of Trent and the Catholic Reformation set Catholic practice until Second Vatican CouncilHistorical record
The connection
Trent's reforms produced the Roman Missal of 1570, a Latin Mass used almost unchanged across the Catholic world for four centuries, plus seminaries and a standard catechism. Vatican II kept Trent's doctrines but revised its practices: Paul VI's Missal of 1969–70 replaced the 'Tridentine' Mass with one celebrated in local languages.
When and where
Trent, northern Italy, 1545–63; Pius V's Missal, 1570; Vatican II in Rome, 1962–65; Paul VI's new Missal promulgated in April 1969.
Historical evidence
The texts of both councils and both missals; Vatican II's documents cite Trent repeatedly.
Questions and debates
Traditionalists say the old Mass was abandoned needlessly; Benedict XVI widened its use in 2007 and Francis restricted it in 2021. How sharp the break was is still argued.