Council of Trent

The Council of Trent (Latin: Concilium Tridentinum), held between 1545 and 1563 in Trent (or Trento), now in northern Italy, was the 19th ecumenical council of the Roman Catholic Church. Prompted by the Protestant Reformation at the time, it has been described as the "most impressive embodiment of the ideals of the Counter-Reformation." It was the last time a Catholic ecumenical council was organized outside the city of Rome, and the second time a council was convened in the territory of the Holy Roman Empire (the first being the Council of Constance).

The Council issued key statements and clarifications of the Church's doctrine and teachings, including scripture, the biblical canon, sacred tradition, original sin, justification, salvation, the sacraments, the Mass, and the veneration of saints and also issued condemnations of what it defined to be heresies committed by proponents of Protestantism. The consequences of the council were also significant with regard to the Church's liturgy and censorship.

The Council met for twenty-five sessions between 13 December 1545 and 4 December 1563. Pope Paul III, who convoked the council, oversaw the first eight sessions (1545–1547), while the twelfth to sixteenth sessions (1551–52) were overseen by Pope Julius III and the seventeenth to twenty-fifth sessions (1562–63) by Pope Pius IV. More than three hundred years passed until the next ecumenical council, the First Vatican Council, was convened in 1869.

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. A few months later, on 31 October 1517, Martin Luther issued his 95 Theses in Wittenberg.

Luther's position on ecumenical councils shifted over time, but in 1520 he appealed to the German princes to oppose the papal Church at the time, if necessary with a council in Germany, open and free of the Papacy. 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. German Catholics, diminished in number, hoped for a council to clarify matters.

It took a generation for the council to materialise, partly due to papal fears over potentially renewing a schism over conciliarism; partly because Lutherans demanded the exclusion of the papacy from the council; partly because of ongoing political rivalries between France and the Holy Roman Empire; and partly due to the Turkish dangers in the Mediterranean. 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". Saint Peter's Basilica and the Sistine Chapel were used for stabling horses. Pope Clement, fearful of the potential for more violence, delayed calling the council.

Charles V strongly favored a council but needed the support of King Francis I of France, who attacked him militarily. Francis I generally opposed a general council due to partial support of the Protestant cause within France. 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.

In the to-and-fro of medieval politics, Pope Pius II, in his bull Execrabilis (1460) and his reply to the University of Cologne (1463), had set aside the theory of the supremacy of general councils laid down by the Council of Constance, which had also called for frequent ecumenical councils every ten years to cope with the backlog of reform and heresies.