Martin Luther (10 November 1483 18 February 1546) was a Christian clergyman who started the Protestant Reformation. As a priest and theology professor, he confronted indulgence salesman Johann Tetzel with his The Ninety-Five Theses in 1517, nailing them to the door of a church. Luther rejected their idea that freedom from God's punishment of sin could be purchased with money. His refusal to retract all of his writings at the demand of Pope Leo X in 1520 and the Holy Roman Emperor Charles V at the Diet of Worms in 1521 resulted in his excommunication by the pope and condemnation as an outlaw by the emperor. Martin Luther taught that salvation is not from good works, but is a free gift from God, received only by grace through faith in Jesus as redeemer from sin. His theology challenged the authority of the pope of the Roman Catholic Church by teaching that the Bible is the only source of divinely revealed knowledge. He taught that catholic priests were unnecessary intermediaries, and that all baptised Christians are in direct communication with God. Those who identify with Luther's teachings are called Lutherans. His translation of the Bible from Latin into German made it more accessible, causing a tremendous impact on the church and on German culture. It fostered the development of a standard version of the German language, added several principles to the art of translation, and influenced the translation into English of the King James Bible. His hymns inspired the development of singing in churches. His marriage to Katharina von Bora set a model for the practice of clerical marriage, allowing Protestant priests to marry. In his later years, Luther became anti-Semitic, writing that Jewish homes should be destroyed, their synagogues burned, money confiscated and liberty curtailed. These statements have made Luther a controversial figure among many historians and religious scholars. His statements were used in Nazi propaganda. However his teachings that individuals have direct access to God and should follow their conscience became a foundation for many who resisted the Nazis. One anti-Nazi activist and Lutheran minister, Dietrich Bonh ffer, died at the hands of the Nazis.