In 1517, Martin Luther set out to reform the Catholic Church by nailing his famed 95 Theses to the door of the Wittenberg Castle. He challenged the power of the pope, the sale of indulgences, purgatory and other ideas. His teachings spread like wild fire and soon gave birth to both the Reformation and "Lutherans" as his followers were called. He had no intention of founding a new church but by 1619 it had spread even to America. Today, many Lutheran churches still hold to Luther's beliefs (such as justification by faith through grace alone and the universal priesthood of believers) which were codified into The Book of Concord after his death. Therefore, many Lutheran churches are similar in their theology. However, some have left this book and adopted more liberal teachings.