On his return to his Wittenberg convent, Luther was made sub-prior. At the university he entered fully upon all the rights and duties of a teacher of theology, having been made licentiate and doctor. Here again it was Staupitz, his friend and spiritual superior, who urged this step: Luther's own wish was to leave the university and devote himself entirely to the office of his Order. The Elector Frederick, who had been struck with Luther by hearing one of his sermons, took this, the first opportunity, of showing him personal sympathy, by offering to defray the expenses of his degree. Luther was reluctant to accept this, and years after he was fond of showing his friends a pear-tree in the courtyard of the convent, under which he discussed the matter with Staupitz, who, however, insisted on his demand. He must have felt the more sensibly the responsibility of his new task, from his own personal strivings after new and true theological light. It was a satisfaction to him afterwards, amidst the endless and unexpected labours and contests which his vocation brought with it, to reflect that he had undertaken it, not from choice, but so entirely from obedience. 'Had I known what I now know,' he would exclaim in his later trials and dangers, 'not ten horses would ever have dragged me into it.' After the necessary preliminaries and customary forms, he received on October 4, 1512, the rights of a licentiate, and on the 18th and 19th was solemnly admitted to the degree of doctor. As licentiate he promised to defend with all his power the truth of the gospel, and he must have had this oath particularly in his mind when he afterwards appealed to the fact of his having sworn on his beloved Bible to preach it faithfully and in its purity. His oath as doctor, which followed, bound him to abstain from doctrines condemned by the Church and offensive to pious ears. Obedience to the Pope was not required at Wittenberg, as it was at other universities. Others, besides Staupitz, expected from the beginning something original and remarkable from the new professor. Pollich, the first great representative of Wittenberg in its early days, and who died in the following year, said of him, 'This monk will revolutionise the whole system of Scholastic teaching.' He seems, like others whom we hear of afterwards, to have been especially struck with the depth of Luther's eyes, and thought that they must reveal the working of a wonderful mind. A new theology, in fact, presented itself at once to Luther in the subject which, as doctor, he chose and exclusively adhered to in his lectures. This was the Bible, the very book of which the study was so generally undervalued in School-theology, which so many doctors of theology scarcely knew, and which was usually so hastily forsaken for those Scholastic sentences and a corresponding exposition of ecclesiastical dogmas.