Trent

Trent was chosen for a general council because of where it sat rather than what it was. A council to answer the Reformation had been demanded for two decades, and the two parties wanted it in different places: the emperor wanted it inside the Empire, the pope wanted it in Italy and under his own hand. Trent, a prince bishopric within the Empire but Italian in language and lying on the road over the Brenner pass, satisfied both descriptions well enough to open in December 1545 under its prince bishop Cristoforo Madruzzo. It sat in three separated periods, 1545 to 1547, 1551 to 1552 and 1562 to 1563, with the sessions moved briefly to Bologna in a dispute over control that the emperor treated as a papal manoeuvre.

Attendance was thin at the start, with about thirty voting bishops, and heavily Italian throughout, which is one of the standing criticisms of it. Protestant representatives were present only during the second period and left without engaging, since the council had already decided the questions they wanted reopened. Eighteen years passed between the first session and the last, four popes died in the course of it, and the men who closed it in December 1563 were mostly not the men who had opened it.

The decrees of Trent fall into two kinds, doctrine and reform, and it issued them in pairs at almost every session. On doctrine it fixed the canon of scripture to include the books the Reformers set aside as apocryphal, declared the Latin Vulgate the authentic text for public use, and ruled that the gospel is contained both in written books and in unwritten traditions. Its decree on justification, the longest and most carefully argued document it produced, held that a person is genuinely made righteous rather than only accounted so, and that free will co-operates with grace without earning it. It confirmed seven sacraments, defined transubstantiation, and upheld the sacrifice of the Mass, communion under one kind for the laity, purgatory, indulgences and the invocation of saints.

On reform it required bishops to reside in their dioceses, ended the holding of several benefices at once, and ordered every diocese to establish a seminary, which is the single measure with the widest practical effect. The liturgical books issued afterwards under papal authority, the catechism, the breviary and the missal, standardised worship across the Latin church for four centuries and gave the Tridentine Mass its name. That rite, and the question of who may celebrate it and by whose permission, remains a live division within Catholicism sixty years after the Second Vatican Council revised the liturgy.