The dangers which threatened Luther, and through him also the honour and prosperity of his Order, affected further his companions and friends who belonged to it. And of this Miltitz took advantage to renew his attempts at mediation. He induced the brethren, at a convention of Augustinian friars held at Eisleben, to persuade Luther once more to write to the Pope, and solemnly assure him that he had never wished to attack him personally. A deputation of these monks, with Staupitz and Link at their head, came to Luther at Wittenberg on the 4th or 5th of September, and received his promise to comply with their wishes. At this convention, Staupitz, who felt his strength no longer equal to the difficult questions and controversies of the time, had resigned his office as Vicar of the Order, and Link had succeeded him. Luther saw him now at Wittenberg for the last time. He retired in quiet seclusion to Salzburg, where the Archbishop was his personal friend. But Luther's spirit would not let him desist for a moment from prosecuting his contest with Rome. He had yet 'a little song' to sing about her. He was in fact at work in August, while rumours were already afloat that Eck was on his way with the bull, upon a new tract, and had even begun to have it printed. It was to treat of the 'Babylonian Captivity of the Church,' taking as its subject the Christian sacraments. Luther knew that in this he cut deeper into the theological and religious principles of the Church, which had come under discussion in his quarrel with Rome, than in all his demands for reform, put forward in his address to the nobility. For while, in common with the Church herself, he saw in the Sacraments, instituted by Christ, the most sacred acts of worship, and the channels through which salvation itself, forgiveness, grace, and strength are imparted from above, in those principles he saw them limited by man's caprice in their original scope and meaning, robbed of their true significance, and made the instruments of Papal and priestly domination, while other pretended sacraments were joined to them, never instituted by Christ. On this account he complained of the tyranny to which these sacraments, and with them the Church, were subject, of the captivity in which they lay. Against him were arrayed not only the hierarchy, but the whole forces of Scholastic learning. He knew that what he now propounded would sound preposterous to these opponents; he would make, he said, his feeble revilers feel their blood run cold. But he met them in the armour of profound erudition, and with learned arguments lucidly and concisely expressed in Latin. At the same time his language, where he explains the real essence of the sacraments, shows a clearness and religious fervour which no layman could fail to understand.