Martin Luther (November 10, 1483 - February 18, 1546) was a German monk, theologian, university professor, Father of Protestantism, and church reformer whose ideas influenced the Protestant Reformation and changed the course of Western civilization. Luther's theology challenged the authority of the papacy by holding that the Bible is the only infallible source of religious authority. On October 31, 1517, Luther wrote to Albrecht, Archbishop of Mainz and Magdeburg, protesting the sale of indulgences. He enclosed in his letter a copy of his "Disputation of Martin Luther on the Power and Efficacy of Indulgences," which came to be known as The 95 Theses.