The Diet of Worms, called by Holy Roman Emperor Charles V to address Luther's religious views, begins in Germany on January 23, 1521.
Martin Luther arrived on April 16, making his famous defense of his beliefs on April 17 and 18, 1521 and refusing to recant his writing unless they can be proven wrong by the Bible or reason. On May 25, 1521: The Edict of Worms is issued, declaring Luther an outlaw and a heretic.