On 15 March 1517, the Fifth Council of the Lateran closed its activities with a number of reform proposals (on the selection of bishops, taxation, censorship and preaching) but not on the new major problems that confronted the Church in Germany and other parts of Europe.

After the Pope condemned in Exsurge Domine fifty-two of Luther's theses as heresy, German opinion considered a council the best method to reconcile existing differences.

[9][10] Under Pope Clement VII (1523–34), mutinous troops many of whom were Lutheran belonging to the Catholic Holy Roman Emperor Charles V sacked Papal Rome in 1527, "raping, killing, burning, stealing, the like had not been seen since the Vandals".

Charles' younger brother Ferdinand of Austria, who ruled a huge swath of territory in central Europe, agreed in 1532 to the Nuremberg Religious Peace granting religious liberty to the Protestants, and in 1533 he further complicated matters when suggesting a general council to include both Catholic and Protestant rulers of Europe that would devise a compromise between the two theological systems.

This proposal met the opposition of the Pope for it gave recognition to Protestants and also elevated the secular Princes of Europe above the clergy on church matters.

Faced with a Turkish attack, Charles held the support of the Protestant German rulers, all of whom delayed the opening of the Council of Trent.

[14] Martin Luther had appealed for a general council, in response to the Papal bull Exsurge Domine of Pope Leo X (1520).

In 1522 German diets joined in the appeal, with Charles V seconding and pressing for a council as a means of reunifying the Church and settling the Reformation controversies.

The decrees were signed in 1563 by 255 members, the highest attendance of the whole council,[15] including four papal legates, two cardinals, three patriarchs, twenty-five archbishops, and 168 bishops, two-thirds of whom were Italians.

[16] Pope Paul III (1534–1549), seeing that the Protestant Reformation was no longer confined to a few preachers, but had won over various princes, especially in Germany, to its ideas, desired a council.

Pope Paul III then initiated several internal Church reforms while Emperor Charles V convened with Protestants and Cardinal Gasparo Contarini at the Diet of Regensburg, to reconcile differences.

Unable, however, to resist the urging of Charles V, the pope, after proposing Mantua as the place of meeting, convened the council at Trent (at that time ruled by a prince-bishop under the Holy Roman Empire),[13] on 13 December 1545; the Pope's decision to transfer it to Bologna in March 1547 on the pretext of avoiding a plague[3] failed to take effect and the council was indefinitely prorogued on 17 September 1549.

None of the three popes reigning over the duration of the council ever attended, which had been a condition of Charles V. Papal legates were appointed to represent the Papacy.

[20] Reopened at Trent on 1 May 1551 by the convocation of Pope Julius III (1550–1555), it was broken up by the sudden victory of Maurice, Elector of Saxony over Emperor Charles V and his march into surrounding state of Tirol on 28 April 1552.

[3] During the second period, the Protestants present asked for a renewed discussion on points already defined and for bishops to be released from their oaths of allegiance to the Pope.

The council was reconvened by Pope Pius IV (1559–1565) for the last time, meeting from 18 January 1562 at Santa Maria Maggiore, and continued until its final adjournment on 4 December 1563.

[22] The French monarchy boycotted the entire council until the last minute when a delegation led by Charles de Guise, Cardinal of Lorraine finally arrived in November 1562.

[24] Jus novum (c. 1140-1563) Jus novissimum (c. 1563-1918) Jus codicis (1918-present) Other Sacraments Sacramentals Sacred places Sacred times Supra-diocesan/eparchal structures Particular churches Juridic persons Philosophy, theology, and fundamental theory of Catholic canon law Clerics Office Juridic and physical persons Associations of the faithful Pars dynamica (trial procedure) Canonization Election of the Roman Pontiff Academic degrees Journals and Professional Societies Faculties of canon law Canonists Institute of consecrated life Society of apostolic life The main objectives of the council were twofold: Specific issues that were discussed included: The doctrinal decisions of the council were set forth in decrees (decreta), which are divided into chapters (capita), which contain the positive statement of the conciliar dogmas, and into short canons (canones), which condemn incorrect views (often a Protestant-associated notion stated in an extreme form) with the concluding anathema sit ("let him be anathema" i.e., excluded from the society of the faithful).

The sacrifice of the Mass was to be offered for dead and living alike and in giving to the apostles the command "do this in remembrance of me," Christ conferred upon them a sacerdotal power.

The practice of withholding the cup from the laity was confirmed (twenty-first session) as one which the Church Fathers had commanded for good and sufficient reasons; yet in certain cases the Pope was made the supreme arbiter as to whether the rule should be strictly maintained.

[28] However, elements of the Prône, the vernacular catechetical preaching service common in the medieval High Mass (and some extra-liturgical situations)[31] became mandatory for Sundays and feast days (fifth session, chapter 2).

[32]: 728 The council appointed, in 1562 (eighteenth session), a commission to prepare a list of forbidden books (Index Librorum Prohibitorum), but it later left the matter to the Pope.

[13] The catechism embodied the council's far-reaching results, including reforms and definitions of the sacraments, the Scriptures, church dogma, and duties of the clergy.

Although the disciplinary or moral reformatory decrees were never published by the throne, they received official recognition at provincial synods and were enforced by the bishops.

Pius IV sent the decrees to Mary, Queen of Scots, with a letter dated 13 June 1564, requesting that she publish them in Scotland, but she dared not do it in the face of John Knox and the Reformation.

Commonly used Latin editions are by Judocus Le Plat (Antwerp, 1779) and by Johann Friedrich von Schulte and Aemilius Ludwig Richter (Leipzig, 1853).

[13] The original acts and debates of the council, as prepared by its general secretary, Bishop Angelo Massarelli, in six large folio volumes, are deposited in the Vatican Library and remained there unpublished for more than 300 years and were brought to light, though only in part, by Augustin Theiner, priest of the oratory (d. 1874), in Acta genuina sancti et oecumenici Concilii Tridentini nunc primum integre edita (2 vols., Leipzig, 1874).