The first three sessions were occupied by preliminary matters, after which the actual business commenced. The constitution of the assembly, as well as the form of procedure, was governed by arbitrary rules. The legates presided as the representatives of the pope; who also appointed the secretaries and other officers. Bishops alone were allowed to vote, but an exception was made in the case of certain abbots and generals of orders, for whose admission no precedent could however be alleged, but such as would be equally availing for all presbyters. Proxies were generally refused, although some were allowed by the sole authority of the pope. All discussions were confined to previous congregations, and in the sessions which followed there was no deliberation, but only the acceptance or rejection of the proposed conclusions. The judgments of the council were embodied partly in decrees which profess to contain the Catholic doctrine on the points in question, partly in canons by which the contrary opinions are anathematized as heretical.

In the fourth session, which was held April 5, 1546, somewhat less than fifty bishops being present, it was decreed that the canon of Scripture includes the books commonly called apocryphal, and that tradition is to be received as of equal authority with the written Word; that the Vulgate is to be taken for the standard text, and no interpretation allowed but such as the Church has affixed. In the fifth session the decree on original sin was passed; in the sixth, that on justification; and in the seventh, that on the sacraments in general, and baptism and confirmation in particular. In the eighth session, the removal to Bologna was appointed, where the two following sessions were held; but no decrees were passed, and in September, 1547, the council was prorogued. The translation to an Italian city had been made under a bull of Paul III., when the German bishops were urgent for reformation, and there seemed no other escape. A disease which broke out at Trent was the alleged excuse. In 1551 the council was again convened by Julius III., who had been present at a former period as legate. The eleventh and twelfth sessions were spent in formal business; in the thirteenth the sacrament of the eucharist was treated; in the fourteenth, the sacraments of penance and extreme unction; in the fifteenth, a safe-conduct was granted to the Protestants; and in the sixteenth, which was held in April, 1552, the prorogation of the council for two years was decreed. Paul IV. was, however, resolutely opposed to its revival, on the ground that his authority was higher than that of a synod, which was therefore needless; and by the threat of secular reformation he deterred some princes from urging the reassembling of the council, which did not take place till January, 1562, when the seventeenth session was held under Pius IV. In the eighteenth, certain of the fathers were appointed to prepare an index of prohibited books, and at the same time, the safe-conduct was removed; in the eighteenth and nineteenth no business was transacted; in the twenty-first, the communion under one kind was enjoined for all, except the celebrant; in the twenty-second, the sacrifice of the mass was declared to be a true and Catholic doctrine; in the twenty-third, the subject handled was the sacrament of order; in the twenty-fourth, the sacrament of matrimony; and in the twenty-fifth, decrees were passed on purgatory, the invocation of saints, the worship of relics and images, indulgences, fasting, the index of prohibited books, the catechism, the breviary, and the missal. After which, the decrees passed under Paul III. and Julius III. were read, and the council was dissolved.

In reviewing the history of this remarkable assembly, it is impossible to overlook the want of unity both in purpose and opinion among its members. The representatives of the emperor of Germany, of the kings of France and Spain, of the duke of Bavaria, and of other secular princes, urgently demanded the reformation of the Church, while the partisans of the Roman court were desirous only to suppress Protestantism. There were none but Italians on whom the pope could entirely depend, for even the Spanish prelates wished his power to be restrained, and that of other bishops to be enlarged. The Germans and French demanded the restoration of the cup, and the marriage of the clergy, while the Spaniards, who opposed them on these points, were united with them on some others against the Roman faction. One great party was urgent that the later sessions should be declared a continuation of the earlier, while another vehemently opposed the declaration; and the council never ventured to rule the question either way. There were endless conflicts between the bishops and the monastic orders, and of Franciscans and Dominicans, with each other. Whether the Blessed Virgin was conceived without sin; what is the true nature of transubstantiation; whether Christ offered himself in the holy supper; whether the apostles were ordained priests at that time or previously,—were among the topics of vehement contention. On the subject of the great doctrine of justification by faith, the members of the council were far from being agreed, and it is beyond denial that some of them held the Protestant view. Even the scanty number, who ventured to decide on the canon of Scripture, and on tradition, were at variance among themselves. Some disputes lasted throughout the whole period, such as whether the council should be said to represent the universal Church; whether the legates should have the privilege of proposing all matters for debate; and whether doctrine should precede reformation. The question of the residence of bishops, that is, whether it is binding by Divine ordinance, or by the law of the Church, in which important considerations were involved, excited long and angry conflicts. Day after day, through weeks and months of the most critical period, the dispute was renewed. The legates themselves were divided; and at one time the dissolution of the council seemed inevitable.

There are many controverted points on which the council gives no information, and they are the very questions which it was most important to decide. No one can learn from its decrees, for instance, what is the sound doctrine about purgatory, nor in what due veneration for images consists, nor which is the sacramental form in penance, or matrimony, nor what is the nature of original sin, nor what is the proper definition of a sacrament. There were some subjects debated more than sufficiently, but left at last undecided; and there were some positions which the council could not renounce, because this would have contradicted the decrees of former popes and councils, and which they could not affirm, because they were opposed by powerful members of the existing Church.

In spite, however, of the imperfect and contradictory statements of the Fathers of Trent, they had no hesitation in pronouncing judgment on what they esteemed Lutheran opinions. We can indeed find no parallel for the prodigality of their curses, unless we go back to the days of the Donatists. They reach not only to those whom the Church of all ages has called blessed, but to many also of the doctors most esteemed in the Roman communion itself. If any one, for example, denies that the works of justified persons are truly meritorious of eternal life, or that the mass is a true and propitiatory sacrifice, or that the custom of confessing privately to a priest has existed from the apostolic age, or that the Church has power to change an institution of Christ, he falls under the imprecation of the council. In the decree of the last session on the invocation of saints, and the use of images and relics, an anathema is pronounced, not only against those who teach, but those who even think differently. And yet the synod which spoke with so much boldness had no claim, either from numbers or character, to be taken as the representative of the Catholic Church. In the first seven sessions held under Paul III., when the ground was laid for maintaining all the errors and corruptions of the Roman Church, less than sixty bishops were present. In the thirteenth, under Julius III., when transubstantiation and the worship of the host were defined, only forty-five bishops and two cardinals were assembled. And in the ninth session there were only thirty-five collected, who yet presumed to take the title of an Ecumenical Council. In the later sessions held under Pius IV., there was a greater number of bishops at Trent; but the chief subjects in dispute had been ruled in the earlier periods of the council, and the deficiency of numbers was not remedied by any subsequent confirmation. Of those who were present, the chief part were Italians; some were bishops of inconsiderable sees, and some mere titulars. There were among them not a few, who subsisted on pensions granted by the pope.

The council was in no sense the free assembly to which Luther and others had appealed, for it was guided throughout by papal influence; and, as the Protestants complained in 1546, it was not convened in a neutral place, while the pope, who was the great delinquent on trial, was allowed to be the judge in his own cause. There were external causes at work, which prevented the freedom of debate. At the very time when the doctrine of justification was under review, a league was formed between the pope and the emperor, for putting down the Protestants; and while the council was debating, the bishop of Rome was sending his contingent of troops. In the council itself, the legates assumed unreasonable authority, and their interruptions were the subject of continual complaint. During the later sessions, the Inquisition was in full force, and there were persons present in the council who had been sufferers. The assembly was overborne by Italian prelates. At one time, when very important subjects were under discussion, there were no more than two bishops to represent the Church of France. On another occasion, forty bishops were sent by the Roman court for the purpose of carrying a particular point, by outvoting the Spanish bishops, by whom it was opposed. We find the ambassadors of secular princes expressing in the strongest language their sense of the tyranny under which the council was held, and by which its freedom was annihilated.

No one who considers these circumstances can wonder that the beneficial reforms of the Church did not result, which had been so long expected and so anxiously desired. They had been demanded, but in vain, by the emperor, and other great princes, as well as by diets and other assemblies of the empire. Even as late as 1563, the French ambassador delivered a list of thirty-four articles of required reformation. After the twenty-second session we find the Imperialists affirming that none of the desired changes had been proposed. And just before the close of the council, the Spanish ambassador came to the legates with a written complaint, that the principal things for which it was assembled had been omitted, and the rest carried with precipitation. The French envoy filled the letters which he addressed to his court with similar testimony. Whatever beneficial changes in the administration of Church affairs seemed to have been made, were neutralized by the terms in which the rights of the see of Rome were reserved, and which were vague enough to admit every abuse, the pope himself being constituted judge in each case, and possessing also a dispensing power.

The last session was brought hastily to a close, partly through the diplomatic skill of the legate Morone; but chiefly on account of the illness of the pope, because everybody knew that if he died during the sitting of the assembly, a schism was inevitable.

The history of the council was written, in 1619, by Sarpi, and forty years later by Cardinal Pallavicini. The former was the most learned person of the age, a statesman and historian as well as a divine; the latter is chiefly known as an apologist of the court and Church of Rome. His work has been described as more injurious to papal interests than that of his predecessor; because if the one has shown how much may be said against the Council of Trent, the other has made it equally plain how little can be alleged in its defence.

The decrees of the council were signed by only 255 members: four of these were legates of the papal see; two, cardinals; three, patriarchs; twenty-five, archbishops; one hundred and sixty-eight, bishops; thirty-nine, deputies of absent prelates; seven, abbots; and seven were generals of religious orders. The Greek Church and the English Church were not represented. It was subscribed on separate schedules, by the ambassadors of the sovereigns who still adhered to the Romish system.