Lutheranism takes its name from its great apostle, Martin Luther. Luther was born in Eisleben in Germany in 1483 of a poor family whose ancestors had been peasants. Martin early showed himself bold, headstrong, willing to pit his own opinions against those of the world, but yet possessing ability, tact, and a love of sound knowledge. Educated at the university of Erfurt, where he became acquainted with the humanistic movement, young Martin entered one of the mendicant orders--the Augustinian--in 1505 and went to live in a monastery. In 1508 Luther was sent with some other monks to Wittenberg to assist a university which had been opened there recently by the elector of Saxony, and a few years later was appointed professor of theology in the institution. [Sidenote: Justification by Faith] While lecturing and preaching at Wittenberg, where he was very popular, Luther developed from the writings of St. Paul and St. Augustine an important doctrinal conviction which differed widely from the faith of the Catholic Church. It concerned the means of eternal salvation. The Church taught, as we have seen, that she possessed the sole means, and that every Christian must perform certain "good works" in order to secure salvation. Luther, on the other hand, became convinced that man was incapable, in the sight of God, of any good works whatsoever, and could be saved only by faith in God's promises. In other words, this monk placed his doctrine of "justification by faith" in opposition to the generally accepted belief in "justification by faith and works." [Sidenote: Tetzel's "Sale" of Indulgences] So far, Luther certainly had no thought of revolting against the authority of the Church. In fact, when he visited Rome in 1511, it was as a pious pilgrim rather than as a carping critic. But a significant event in the year 1517 served to make clear a wide discrepancy between what he was teaching and what the Church taught. That year a certain papal agent, Tetzel by name, was disposing of indulgences in the great archbishopric of Mainz. An indulgence, according to Catholic theology, was a remission of the temporal punishment in purgatory due to sin, and could be granted only by authority of the Church; the grant of indulgences depended upon the contrition and confession of the applicant, and often at that time upon money-payments. Against what he believed was a corruption of Christian doctrine and a swindling of the poorer people, Luther protested in a series of ninety-five Theses which he posted on the church door in Wittenberg (31 October, 1517). [Sidenote: The Ninety-five Theses]