Luther (1483 - 1546), the leader of the Reformation in Germany, was born in Eisleben. He became an Augustinian friar and was ordained priest in 1507. In 1512 he was appointed Professor of Biblical Theology at the University of Wittenberg by Frederick the Wise, Elector of Saxony, for whom Cranach had earlier worked as court painter. On 31 October 1517 Luther nailed his 95 Theses to the door of All Saint's Church in Wittenberg protesting at the sale of papal indulgences. This led to public debate about corruption in the Catholic Church and about church doctrine itself, and sparked off the Reformation.
Luther was excommunicated in 1520 and condemned by Emperor Charles V after the Diet of Worms in 1521. From then on Luther formulated his own ideas, which centred around the belief in justification (salvation) by faith alone, without the need for the mediation of the Church, a concept criticised by Erasmus.