Definition of Luther, Martin
- (1483–1546), German Protestant theologian, the principal figure of the German Reformation. He preached the doctrine of justification by faith rather than by works and attacked the sale of indulgences (1517) and papal authority. In 1521 he was excommunicated at the Diet of Worms. His translation of the Bible into High German (1522–34) contributed significantly to the development of German literature in the vernacular.