In 1508, Luther was summoned by Staupitz to teach at the university of Wittenberg, just founded by Frederick the Wise of Saxony. In 1510, he visited Rome, a visit which only served to strengthen him in his conviction that spiritual pride, the characteristic fault of the Renaissance, was the enemy to be withstood, and to deepen his dislike of those ceremonial observances of the Church which consecrated the belief in the efficacy of works. Luther had returned to Wittenberg to carry on his teaching, when the visit of Tetzel, a Dominican, to Germany, offering papal indulgences to those who would contribute money to the building of St. Peter’s at Rome, aroused him to immediate action. The doctrine of indulgences originated in the not unnatural view, that while penitence reconciled the sinner to God, the wrong done to man had yet to be punished, and that the punishment, like that for worldly offences, could be commuted by a fine. But the system had been shamefully abused. The Church declared that she held, in the works of supererogation of the faithful, a treasure from which she could draw for the remission of penalties, and, in her eager desire to gain money, granted indulgences carelessly and without insisting on the previous penitence of the offender. She even claimed the power of remitting the punishment of those in purgatory. Whatever may be said in defence of the primitive system of indulgences, it cannot be denied that in their exaggerated form they led to grievous abuse, and involved a flat denial of the necessity of grace. Accordingly Luther, in pursuance of academic custom, nailed on the door of the church at Wittenberg his famous ninety-five theses, in which he controverted the theory of indulgences, and challenged all comers to disprove the correctness of his statements (October 17, 1517).