On the other hand, the very impunity with which this traffic in indulgences had been maintained throughout German Christendom, had served to increase from day to day the audacity of its promoters. Ranged on the side of these doctrines of Thomas Aquinas, the chief mainstay of this trade, stood the whole powerful order of the Dominicans. And to this order Tetzel himself, the sub-commissioner of indulgences, belonged. Already other doctrines of the Pope's authority, of his power over the salvation of the human soul, and the infallibility of his decisions, had been asserted with ever-increasing boldness. The mediaeval writings of Thomas Aquinas had conspicuously tended to this result. And a climax had just been reached at a so-called General Council, which met at Rome shortly after Luther's visit there, and continued its sittings for several years. Tetzel, who hitherto had only made himself notorious as a preacher, or rather as a bawling mountebank, now answered Luther with two series of theses of his own, drawn up in learned scholastic form. One Conrad Wimpina, a theologian of the university of Frankfort-on-the-Oder, whom the Archbishop Albert had recommended, assisted Tetzel in this work. The university of Frankfort immediately made Tetzel doctor of theology, and thus espoused his theses. Three hundred Dominican monks assembled round him while he conducted an academical disputation upon them. The doctrines he now advanced were the doctrines of Thomas Aquinas. But at the same time he took care to make the question of the Pope's position and power the cardinal point at issue; he and his patrons knew well enough, that for Luther, who in his theses had touched upon this question so significantly though so briefly, this was the most fatal blow that he could deal. 'Christians must be taught,' he declared, 'that in all that relates to faith and salvation, the judgment of the Pope is absolutely infallible, and that all observances connected with matters of faith on which the Papal see has expressed itself, are equivalent to Christian truths, even if they are not to be found in scripture.' With distinct reference to his opponent, but without actually mentioning him by name, he insists that whoever defends heretical error must be held to be excommunicated, and if he fails within a given time to make satisfaction, incurs by right and law the most frightful penalties. Furthermore, he argued--and this has always been held up against Luther and Protestantism--that if the authority of the Church and Pope should not be recognised, every man would believe only what was pleasing to himself and what he found in the Bible, and thus the souls of all Christendom would be imperilled.