The first doctrinal issue the Council wanted to address was the question of the Original Sin of Adam. But since the Reformers had directly attacked the authority of the Church., insisting doctrine could only be decided by SCRIPTURE ALONE, the Council decided to first answer these questions, Which books should be included in the Bible?
The early Church had decided by consensus which books would be included in the New Testament canon after the Marcion controversy, but the early Church had no reason to decide on which Old Testament books were considered canonical. Jerome, the early Church Father who translated the Latin Catholic Vulgate Bible from Hebrew and Greek, argued against including in the Old Testament canon the books written in Greek like Tobit, Judith, and Maccabees, as their canonicity was debated by early Jewish councils. Other Church Fathers such as St. Augustine argued for the wider canon including these disputed books. Catholics refer to these Old Testament books written in Greek as deutero-canonical, whereas Protestants refer to them as the Apocrypha. The apocryphal books are usually excluded from Protestant Bibles, although sometimes they are in an appendix, whereas they are included in Catholic and Orthodox Bibles.
Luther was not overly fond of the book of James, calling it a “gospel of straw,” as it proclaimed that faith without works is dead, apparently conflicting with the “faith alone” Lutheran slogan. The Book of Concord, the doctrinal summation of early Lutheran doctrine, does not mention the New Testament canon. However, the Protestant and Catholic canon have always included the same books in the New Testament.
The Council of Trent considered reaffirming the decision of the Council of Florence a century to adapt the wider Old Testament canon without taking a stand on the status of the deutero-canonical or apocryphal books. The decree promulgated simply lists the books of the Old and New Testament, including the deutero-canonical books.
Subsequent interpretations in later years became more strident. The inadequacies of the Vulgate translation were known, and after the council concluded it was updated based on more recent scholarship.
For all the ink spilled and arguments raged over the equality of Scriptures and Tradition over subsequent centuries, the decrees spend a paragraph (DS 1501) on this issue. The decree speaks of the “written books and unwritten traditions (O’Malley emphasizes, traditions with a small t) that have come down to us,” that the Church “receives and venerates with the same sense of loyalty and reverence all the books of the Old and New Testament, for the One God is author of both, together with all the traditions concerning faith and practice, as coming from the mouth of Christ or being inspired by the Holy Spirit and preserved in continuous succession in the Catholic Church.” The Council’s decree also stated that the Latin Vulgate translation was an authentic version, but it did not ban other Latin translations nor did it forbid vernacular translations. The decree also does not discuss the relative importance of Scriptures and Tradition.
At Trent, the concise decrees were firmer than the discussions. Since the minutes of the council were sealed the Council gained a reactionary reputation that was distorted. Furthermore, in a bull in 1564 Pope Pius IV went further, restricting vernacular translations of the Bible and forbidding biblical commentaries unless they were approved by the Holy See.
The bull of Pope Pius IV did not mention whether a vernacular missal would be allowed, which in time evolved into the false belief that Trent forbade celebrating the liturgy in the vernacular.
ORIGINAL SIN AND JUSTIFICATION
The Council wanted to address Justification, a key issue with the Lutherans, but first they needed to address the doctrine of Original Sin of Adam when he and Eve ate the apple in the Garden of Eden. The Catholic position on these two important doctrinal issues both at the Councils of Trent and Vatican II were not as far apart as the polemicists on both sides would claim. Quoting O’Malley, “St Paul in Romans 5 and First Corinthians 14 taught that through Adam’s ‘Fall’ sin and death came into the world.” According to St Augustine, “Adam’s sin was transmitted from parents to children and affected all members of the human race. Although Christ redeemed the world from sin, concupiscence (tendency to sin) remained even in the baptized.”
Some Catholics attacked Luther’s teaching that the concupiscence of “Original Sin remained even in the baptized; that concupiscence was itself a sin in the full sense of the word rather than an inclination to sin, and that Luther insisted on the total corruption of human nature and the utter impotence of the human will regarding salvation.” The Council of Trent affirmed the Catholic teaching that baptism washed away the stain of Original Sin, that the concupiscence remaining in us is not actual sin but rather the tendency to sin, and that we do not share in the guilt of Adam.  The council decrees say that “concupiscence or the tinder of sin remains in the baptized. Since it is left for us to wrestle with, it cannot harm those who do not consent but manfully resist it by the grace of Jesus Christ.” Included in the section of Original Sin was a short paragraph affirming the practice of infant baptism.
The Council of Trent affirmed justification through faith, but not Luther’s extreme position of justification through faith ALONE. The decrees on Justification from Trent in Denzinger run well over a dozen pages and took seven months for the Council to draft and several pages for O’Malley to summarize, so read O’Malley on this topic. We plan to cover justification in detail much later when we review that section of the Catholic Catechism.
REFORMS AND SACRAMENTS AND POLITICS
Decrees on doctrine had been pronounced, now the Council took up a reform issue that was a sensitive issue because it encroached on the papal power to grant dispensations. The Council passed a decree requiring that if a bishop was drawing income from multiple bishoprics, he should resign from all but one, and that the bishop should visit every church in his diocese every year, and that preaching and the care of souls would be his primary responsibility. Pope Paul III eased tensions when he issued a bull saying he would no longer grant dispensations allowing multiple bishoprics.
Luther had argued there were only two sacraments, Baptism and the Eucharist. In response, Trent affirmed Catholic teaching that Jesus instituted all seven sacraments. O’Malley writes that the Council made these points, “the sacraments are not equal in dignity, they are necessary for salvation,” they are more than symbolic, they are “efficacious signs” the confer grace, “they must be conferred by the proper minister and be performed using the proper rites.”
Then one of the bishops died from typhus. Everyone was worried that the plague would strike the town of Trent, so they quickly decided to reconvene in Bologna in 1547, not near German lands like the emperor demanded, but in the Papal States. This was a mistake. Emperor Charles V was furious, so was the pope, though he calmed down, many bishops boycotted. The remaining bishops discussed the sacraments for a few years, the Pope bade the Council to dither, nothing was accomplished. Politics intervened, the Pope’s son was brutally assassinated, the emperor was suspected, the pope died, but then Pope Julius III was elected, who made peace with Emperor Charles and reconvened the Council at Trent in 1551.
The emperor twisted the arms of his Lutheran princes to send delegates to the Council, but their polemic positions were too concrete. They came, they bickered, they left.
The Council continued the discussions in Bologna on the sacraments. They discussed offering the cup to the laity, though no decision was made. Since Luther had attacked the sacramental system of the Catholic Church, the Council issued decrees on all the sacraments, which we will study later when we review the Catholic Catechism.
The Council decrees upheld the transubstantiation of the bread and the wine into the Real Presence of the body and blood of Christ, and affirmed the popular adoration of the Eucharist. Adults were obligated to receive the Eucharist at least annually, with confession of serious sins required before communion.
O’Malley quotes the Council decrees as it “enjoins, exhorts, begs, and entreats” all Christians to “believe and reverence these sacred mysteries of His body and blood with such constancy and firmness of faith, such dedication of mind, and such devotion and worship that they may be able to receive frequently this life-support bread. May it be for them truly the life of the soul and the unending health of the mind; thus, strengthened by its force, may they be able after the journey of this wretched pilgrimage to reach the heavenly fatherland, there to eat without end the same bread of angels that they now eat beneath the sacred veil.”
Politics heated back up, France declared war, allying with the Protestants, the emperor lost, the emperor abdicated, splitting the Hapsburg domains in two, the pope died, the next reactionary pope caused problems then died, the Council of Trent was suspended for a decade, and you can read all this continuing shaggy dog history in O’Malley.
 John O’Malley, Trent, ‘What Happened at the Council” (Cambridge, Massachusetts, The Belknap Press of Harvard University Press, 2013), pp. 77-102, and Heinrich Denzinger, Compendium of Creeds, Definitions, and Declarations on Matters of Faith and Morals, 43rd Edition, edited by Peter Hunermann (San Francisco, Ignatius Press, 2012), paragraphs 1501-1508, pp. 370-372.
 John O’Malley, Trent, What Happened at the Council, 266-267
 John O’Malley, Trent, What Happened at the Council, 269
 John O’Malley, Trent, What Happened at the Council, pp. 130-104.
 Denzinger, paragraph 1515, p.373.
 John O’Malley, Trent, What Happened at the Council, pp. 116-121.
 John O’Malley, Trent, What Happened at the Council, pp. 121-147.
 John O’Malley, Trent, What Happened at the Council, 148, he uses a different translation than Denzinger, paragraph 1649, p. 397.
 John O’Malley, Trent, ‘What Happened at the Council” (Cambridge, Massachusetts, The Belknap Press of Harvard University Press, 2013), pp. 157-162.