A sixteenth-century German religious leader; the founder of Protestantism. Luther, a priest of the Roman Catholic Church, began the Reformation by posting his Ninety-five Theses, which attacked the church for allowing the sale of indulgences. He soon became convinced that the Catholic Church was opposed to the Bible (see also Bible) on the question of justification by grace, through faith, and that no accommodation of his beliefs on this point was possible within the church. Luther concluded that reform of the church had to happen through formation of a new body of Christians (see also Christian). He denied the authority of the pope and many other aspects of Catholic teaching, including the doctrine of transubstantiation.