Yes Martin Luther was promised safe passage to and from the Council. The Council was originally scheduled to be held in Mantua, Italy, and to begin May 23, 1537 it was postponed and moved to Bolognia due to the plague, there was a long recess and the Council was finally re-conviened at Trent. So while the original safe passage was granted for Mantua, it was extended to Luther, and other Protestants to attend and explain their theologies. Throughout history many have been promised safe passage to and from various Councils to defend their new doctrines.

(All but the first two lines are from the Catholic Encyclopedia) Easier than typing it out myself. It explains the Catholic position on the events that took place. You will note that not all the Catholics are painted as honorable. The entire article can be found here,
http://www.newadvent.org/cathen/09438b.htm

The Pope sent for Luther, commanding him to appear and explain his teachings. Once the documents reached Luther (7 August) to appear in person within sixty days in Rome for a hearing. He at once took refuge in the excuse that such a trip could not be undertaken without endangering his life; he sought influence to secure the refusal of a safe-conduct through the electorate and brought pressure to bear on the Emperor Maximilian and Elector Frederick to have the hearing and judges appointed in Germany. The university sent letters to Rome and to the nuncio Miltitz sustaining the plea of “infirm health” and vouching for his orthodoxy. His literary activity continued unabated. His “Resolutiones”, which were already completed, he also sent to the pope (30 May). The letter accompanying them breathes the most loyal expression of confidence and trust in the Holy See, and is couched in such terms of abject subserviency and fulsome adulation, that its sincerity and frankness, followed as it was by such an almost instantaneous revulsion, is instinctively questioned. Moreover before this letter had been written his anticipatory action in preaching his “Sermon on the Power of Excommunication” (16 May), in which it is contended that visible union with the Church is not broken by excommunication, but by sin alone, only strengthens the surmise of a lack of good faith. The inflammatory character of this sermon was fully acknowledged by himself.

Influential intervention had the effect of having the hearing fixed during the Diet of Augsburg, which was called to effect an alliance between the Holy See, the Emperor Maximilian, and King Christian of Norway, Denmark, and Sweden, in the war against the Turks. In the official instructions calling the Diet, the name or cause of Luther does not figure.

The papal legate, Cajetan, and Luther met face to face for the first time at Augsburg on 11 October. Cajetan (b. 1470) was “one of the most remarkable figures woven into the history of the Reformation on the Roman side . . . a man of erudition and blameless life” (Weizacker); he was a doctor of philosophy before he was twenty-one, at this early age filling chairs with distinction in both sciences at some of the leading universities; in humanistic studies he was so well versed as to enter the dialectic arena against Pico della Mirandola when only twenty-four. Surely no better qualified man could be detailed to adjust the theological difficulties. But the audiences were doomed to failure. Cajetan came to adjudicate, Luther to defend; the former demanded submission, the latter launched out into remonstrance; the one showed a spirit of mediating patience, the other mistook it for apprehensive fear; the prisoner at the bar could not refrain from bandying words with the judge on the bench. The legate, with the reputation of “the most renowned and easily the first theologian of his age”, could not fail to be shocked at the rude, discourteous, bawling tone of the friar, and having exhausted all his efforts, he dismissed him with the injunction not to call again until he recanted. Fiction and myth had a wide sweep in dealing with this meeting and have woven such an inextricable web of obscurity about it that we must follow either the highly coloured narratives of Luther and his friends, or be guided by the most trustworthy criterion of logical conjecture.

The papal Brief to Cajetan (23 August), which was handed to Luther at Nuremberg on his way home, in which the pope, contrary to all canonical precedents, demands the most summary action in regard to the uncondemned and unexcommunicated “child of iniquity”, asks the aid of the emperor, in the event of Luther’s refusal to appear in Rome, to place him under forcible arrest, was no doubt written in Germany, and is an evident forgery (Beard, op. cit., 257-258; Ranke, “Deutsche Gesch.” VI, 97-98). Like all forged papal documents, it still shows a surprising vitality, and is found in every biography of Luther.

Luther’s return to Wittenberg occurred on the anniversary of his nailing the Theses to the castle church door (31 October, 1518). All efforts towards a recantation having failed, and now assured of the sympathy and support of the temporal princes, he followed his appeal to the pope by a new appeal to an ecumenical council (28 November, 1518), which, as will be seen later, he again, denying the authority of both, followed by an appeal to the Bible.

The appointment of Karl von Miltitz, the young Saxon nobleman in minor orders, sent as nuncio to deliver the Golden Rose to the Elector Frederick, was unfortunate and abortive. The Golden Rose was not offered as a sop to secure the good graces of the elector, but in response to prolonged and importunate agitation on his part to get it (Hausrath, “Luther”, I, 276). Miltitz not only lacked prudence and tact, but in his frequent drinking bouts lost all sense of diplomatic reticence; by continually borrowing from Luther’s friends he placed himself in a position only to inspire contempt. It is true that his unauthorized overtures drew from Luther an act, which if it “is no recantation, is at least remarkably like one” (Beard, op. cit., 274). In it he promised:

1.to observe silence if his assailants did the same;
2.complete submission to the pope;
3.to publish a plain statement to the public advocating loyalty to the Church;
4.to place the whole vexatious case in the hands of a delegated bishop.
The whole transaction closed with a banquet, an embrace, tears of joy, and a kiss of peace only to be disregarded and ridiculed afterwards by Luther. The nuncio’s treatment of Tetzel was severe and unjust. When the sick and ailing man could not come to him on account of the heated public sentiment against him, Miltitz on his visit to Leipzig summoned him to a meeting, in which he overwhelmed him with reproaches and charges, stigmatized him as the originator of the whole unfortunate affair, threatened the displeasure of the pope, and no doubt hastened the impending death of Tetzel (1 August, 1519).

While the preliminaries of the Leipzig Disputation were pending, a true insight into Luther’s real attitude towards the papacy, the subject which would form the main thesis of discussion, can best be gleaned from his own letters. On 3 March, 1519, he writes Leo X: “Before God and all his creatures, I bear testimony that I neither did desire, nor do desire to touch or by intrigue to undermine the authority of the Roman Church and that of your holiness” (De Wette, op. cit., I, 234). Two days later (5 March) he writes to Spalatin: “It was never my intention to revolt from the Roman Apostolic chair” (De Wette, op. cit., I, 236). Ten days later (13 March) he writes to the same: “I am at a loss to know whether the pope be antichrist or his apostle” (De Wette, op. cit., I, 239). A month before this (20 Feb.) he thanks Scheurl for sending him the foul “Dialogue of Julius and St. Peter”, a most poisonous attack on the papacy, saying he is sorely tempted to issue it in the vernacular to the public (De Wette, op. cit., I, 230). “To prove Luther’s consistency to vindicate his conduct at all points, as faultless both in veracity and courage under those circumstances, may be left to myth-making simpletons” (Bayne, op. cit., I, 457).

The Leipzig disputation was an important factor in fixing the alignment of both disputants, and forcing Luther’s theological evolution. It was an outgrowth of the “Obelisci” and “Asterisci”, which was taken up by Carlstadt during Luther’s absence at Heidelberg in 1518. It was precipitated by the latter, and certainly not solicited or sought by Eck. Every obstacle was placed in the way of its taking place, only to be brushed aside. The Bishops of Merseburg and Brandenburg issued their official inhibitions; the theological faculty of the Leipzig University sent a letter of protest to Luther not to meddle in an affair that was purely Carlstadt’s, and another to Duke George to prohibit it. Scheurl, then an intimate of Luther’s, tried to dissuade him from the meeting; Eck, in terms pacific and dignified, replied to Carlstadt’s offensive, and Luther’s pugnacious letters, in fruitless endeavour to avert all public controversy either in print or lecture; Luther himself, pledged and forbidden all public discourse or print, begged Duke Frederick to make an endeavour to bring about the meeting (De Wette, op. cit., I, 175) at the same time that he personally appealed to Duke George for permission to allow it, and this in spite of the fact that he had already given the theses against Eck to the public. In the face of such urgent pressure Eck could not fail to accept the challenge. Even at this stage Eck and Carlstadt were to be the accredited combatants, and the formal admission of Luther into the disputation was only determined upon when the disputants were actually at Leipzig.

The disputation on Eck’s twelve, subsequently thirteen, theses, was opened with much parade and ceremony on 27 June, and the university aula being too small, was conducted at the Pleissenburg Castle. The wordy battle was between Carlstadt and Eck on the subject of Divine grace and human free will. As is well known, it ended in the former’s humiliating discomfiture. Luther and Eck’s discussion, 4 July, was on papal supremacy. The former, though gifted with a brilliant readiness of speech, lacked and his warmest admirers admit it the quiet composure, curbed self-restraint, and unruffled temper of a good disputant. The result was that the imperturbable serenity and unerring confidence of Eck, had an exasperating effect on him. He was “querulous and censorious”, “arbitrary and bitter” (Mosellanus), which hardly contributed to the advantage of his cause, either in argumentation or with his hearers. Papal supremacy was denied by him, because it found no warrant in Holy Writ or in Divine right. Eck’s comments on the “pestilential” errors of Wiclif and Hus condemned by the Council of Constance was met by the reply, that, so far as the position of the Hussites was concerned, there were among them many who were “very Christian and evangelical”. Eck took his antagonist to task for placing the individual in a position to understand the Bible better than the popes, councils, doctors, and universities, and in pressing his argument closer, asserting that the condemned Bohemians would not hesitate to hail him as their patron, elicited the ungentle remonstrance “that is a shameless lie”. Eck, undisturbed and with the instinct of the trained debater, drove his antagonist still further, until he finally admitted the fallibility of an ecumenical council, upon which he closed the discussion with the laconic remark: “If you believe a legitimately assembled council can err and has erred, then you are to me as a heathen and publican” (K??stlin-Kawerau, op. cit., I, 243-50). This was 15 July. Luther returned sullen and crestfallen to Wittenberg, from what had proved to him an inglorious tournament.

Huss was burnt at the stake after the Council of Constance, and it was not the Pope but the King who gave him safe passage. Things may have been different if it was the Pope who had granted him safe passage. However the king of a different land is a different thing.

Thankfully we don’t burn people at the stake anymore. Unfortunatly everyone did then. Calvin in Geneva, Luther encited and encourged executions, (not being a head of state like Calvin, who was both a civil and religious leader) or the Monarch of England who claimed to be both head of the State and the Church. Another thing that is different today is that in most places now, we don’t torture persons to gain a confession. In the times we are discussing everyone (Protestant and Catholic) held that being sinners, nobody would confess their crimes unless they were tortured. (Dunking in water by the Puritains, as well as other ordeals by everyone) So pointing at an execution of one person for heresy does not mean that the other side was blameless.

Very interesting question. One I’ve not heard before. I’ll be hitting the books on that one.

That the Church has infallibly determined what books are in the Canon of scripture is required of believing Catholics. That Trent reaffirmed what earlier Councils and Popes had already stated is also true. (Many Protestants charge that the Catholic Church “added the books” at Trent, which is not true.)

What I have to do is refresh myself as to the timeline of when the Church gave us the official canon. (I believe it was in the mid 300s or early 400’s but I’ll confirm this before I make an “official” statement.

On another topic, infallibility is not always a onetime event. If the Church teaches something, that was defined infallibly, and an individual bishop upholds that dogma of the Faith and teaches it at another time, he is teaching infallibly, because he is stating again what the Church already holds as infallible, so the question may be better asked, when was the Canon of the Bible “First” taught by the Church in an infallible manner.

In the early Church there were several canons accepted by individual groups, or Churches in different parts of the world, it was not until the Church officially taught what the Canon consisted of that it was held as infallible. While it was accepted as authorative, and infallible, the word infallible may not have been used at the time, just as the term Trinity was a later definition to describe what the Church already taught from the beginning.

Sorry have not had a chance to go through the boxes of books yet. I’ll try to make time this week.

Just a thought before I have a chance to look up the answer to your question. Most Protestants are taught that when the Pope, or Catholic Church makes an infallible declaration, it is a “New Dogma” or new teaching. What an Infallible declaration means to a Catholic is a response to a question regarding an important teaching of the Church that some have called into question.

There are any number of statements that people like Hislop and others have written that misinform the Protestant mind.

Beottener and other have written that the Catholic Church added books to the Bible at Trent. This is a false assertion. Trent responding to the editing of Protestant teachers like Luther, who removed those books from the Old Testament, and called into question some of the New Testament, stated in the strongest of words that the Catholic Church maintained the same books as she had previously defined as part of the Canon.

Prior to the definition of the Dogmas of the Immaculate Conception and the Assumption, there was a long history of the celebration of the two feasts in both the Eastern and Western Church. While they were not on the calendars of all the diocese of the world, they were in most. Missals and prayers going back to the early 300’s include both feasts. When the question came up, and some people started to deny that these were authentic Catholic teachings it became important to settle the issue, once and for all. So it was studied, and when the Popes (Pope Piux IX and Pope Pius XII in these two cases) had gathered the information, prayed and felt it was opportune, they made the formal and Infallible declarations, which made the teachings not just an ancient and venerable teaching, but a Dogma, or teaching that one had to recognize in order to be a faithful Catholic.

An example of a teaching that is not Dogma would be Limbo. Limbo is considered a pious belief, it is Theological speculation about what happens to the souls of infants and young children who die without being baptized. One theory is that they go to a place of perfect natural happiness, (as opposed to heaven which is a place of perfect SUPERnatural happiness.) Others believe that God will grant the soul of the unbaptized who had no chance to hear the Gospel or were not baptized through no fault of their own full knowledge of His nature, and they can choose or reject Him. If they choose Him they enter heaven. As the Church has not defined this as Dogma, Catholics are free to accept or reject either notion, and still be considered Catholics in good standing.

So Infallible declarations really don’t “invent” new teachings, but clarify those teachings that have been attacked or come into question. They don’t change what the Church teaches, but rather clarify what has always been taught.