Martin Luther began the Protestant Reformation in Germany in 1517 by nailing his 95 Theses to a church door in Wittenberg. The theses criticized the Catholic Church's sale of indulgences and overreliance on traditions rather than the Bible. Luther argued that salvation comes through faith alone rather than good works. He refused to recant his views and was excommunicated by the pope in 1520. The Holy Roman Emperor declared Luther a heretic in 1521 but he was protected by German princes. By 1522, Luther's teachings had been adopted by local clergy in Wittenberg, establishing Lutheranism as a separate religious movement from Catholicism.