Martin Luther was a German monk who in 1517 nailed his 95 Theses criticizing the Catholic Church's practices, especially selling indulgences, to a church door in Wittenberg. He wanted to reform the Church and believed salvation came through faith alone rather than good works. Though excommunicated, Luther's ideas spread rapidly through pamphlets and the printing press. This led to the establishment of Lutheranism and the Protestant Reformation, dividing Western Christianity between Catholic and Protestant denominations.