Luther's theses now found another assailant, and one stronger even than Tetzel, in the person of a Dominican and Thomist, one Sylvester Mazolini of Prierio (Prierias), master of the sacred palace at Rome, and a confidant of the Pope. He too, like Tetzel, based his chief contention on the question of Papal authority, and was the first to carry that contention to an extreme. The Pope, he said, is the Church of Rome; the Romish Church is the Universal Christian Church; whoever disputes the right of the Romish Church to act entirely as she may, is a heretic. In this way he treated as contemptuously as he could the obscure German, whose theses, that 'bite like a cur,' as he expressed it, he only wished to dismiss with all despatch. Another Dominican, James van Hoogstraten, prior at Cologne, who had already figured as the prime zealot in the affair about Reuchlin, which he was still prosecuting, now demanded, in his preface to a pamphlet on that subject, that Luther should be sent to the stake as a dangerous heretic. But a far more important, and to Luther an utterly unexpected opponent, appeared in the person of John Eck, professor at the university of Ingolstadt, and canon at Eichstädt. He was a man of very extensive learning in the earlier and later Scholastic theology of the Church; he was a sharp-witted and ready controversialist, and he knew how to use his weapons in disputations. He was fully conscious of these gifts, and made a bold push to advance himself by their means, whilst troubling himself very little in reality about the high and sacred issues involved in the dispute. He sought to keep on friendly and useful relations with other circles than those of Scholastic theology, such as with learned Humanists, and a short time before, with Luther himself and his colleague Carlstadt, to whom he had been introduced through a jurist of Nüremberg named Scheuerl. Luther, after the publication of his theses, had written a friendly letter to Eck. What then was his surprise to find himself attacked by Eck in a critical reply entitled 'Obelisks.' The tone of his remarks was as wounding, coarse, and vindictive as their substance was superficial. They aimed a well-meditated blow, by stigmatising Luther's propositions as Bohemian poison, mere Hussite heresy. Eck, when reproached for such a breach of friendship, declared that he had written the book for his bishop of Eichstädt, and not with any view of publication.