Correct me if I am wrong, but I can’t find any evidence that Johann Tetzel was ever imprisoned for his “abuse” of Indulgences. Odd that...
No, he was never imprisoned, but basically later imprisoned himself in depression.
The Catholic Encyclopedia, which labors to clear his name of various charges, and affirms him as a "scholastically-trained theologican" "a bachelor of theology" who, after the publication of Luther's 95 thesis published responses, and was promoted to the doctorate.
And states that, based upon Tetzel's writing if not his preaching, "his teaching regarding the indulgences for the living was correct. The charge that the forgiveness of sins was sold for money regardless of contrition or that absolution for sins to be committed in the future could be purchased is baseless."
For as I myself said , referencing the work of esteemed Catholic Church historian Hubert Jedin (and John Patrick Dolan), what one could purchase was "a confession certificate, by virtue of which one could confess to any priest at any desired time in his later life sins reserved to the pope." And that "since what was actually given in response to a donation was a confession certificate, which required penitent confession...in order to receive the indulgence, then technically it is asserted that Rome never authorized the actual sale of indulgences. Meaning that Rome sold a conditional promise of remission of the temporal punishment due to sin.'' And that this money was partly in order for a Bishop to repay money loaned to him in order to illegally have pastoral office.
What the CE faults Tetzel for was that "regarding indulgences for the dead," "he accepted the mere school opinion of a few obscure writers, which overstepped the contents of papal indulgence Bulls," and in this abuse "Tetzel is in no way to be exonerated."
The CE also informs,
Luther's agitation having frustrated further efforts to popularize the granted indulgence of eight years, Tetzel, deserted by the public, broken in spirit, wrecked in health, retired to his monastery at Leipzig in 1518. Here in the middle of January, 1519, he had to face the bitter reproaches and unjust incriminations of Carl von Meltitz. It was at this time that Luther magnanimously penned a letter in which he tries to console him by declaring "that the agitation was not that of his [Tetzel's] creation, but that the child had an entirely different father". Tetzel died soon after, received an honourable burial, and was interred before the high altar of the Dominican church at Leipzig.
Therefore we see that Rome, which historically exhorted that the one duty of the multitude was to allow themselves to be led, and, like a docile flock, to follow the Pastors, via its highest authority, provided for and permitted the preaching of the offer of a plenary indulgence for those who contributed money and made contrite confession, while basically tolerating abuse of it, till Luther made it an unavoidable issue. Thus Rome, could profit from the long term abuse of such, while at the same time disavow sanction of it.
Note also that I am quoting from Catholic sources, partly in condescension to RCs, and the Catholic Encyclopedia, while often providing testimony than RCs dislike, is overall a biased largely apologetical source. And of course to varying degrees, this charge can be laid at the feet of Protestant sources, but btwn both there is reliable historical truth to be found.
And often the premise of Catholics attacking the Reformation is to anachronistically read certain teaching solidly established by Trent and successors as being likewise established before that, as is the case with the canon of Scripture .
And which may relate to teaching on indulgences. While the CE explains Tetzel as having "accepted the mere school opinion of a few obscure writers, which overstepped the contents of papal indulgence Bulls," and which was condemned shortly later by Cardinal Cajetan, yet it that this was an interpretation prior to that of unclear teaching seems to be the case. From many old sources as here we have this quote from Leo X, "that the dead and the living who truly obtain these indulgences, are immediately freed from the punishment due to their actual sins according to Divine justice, which allows these indulgences to be granted and obtained. "
And from Tetzel's thesis:
That though the pope hath not the power of the keys over the souls in purgatory, he may apply a jubilee by way of suffrage, and that there is no reason to doubt that a soul may go to Heaven the very moment that the alms is cast into the chest...That although the buying of indulgences be not commanded, yet it is advised; and of this the people ought to be put in mind.
But the key phrase is "obtained."