Luther's 95 theses (1517) that attacked indulgences.) In 1519, Johann Eck challenged Karlstadt to the Leipzig Debate. There, Eck debated with Luther as well as Karlstadt. On 15 June 1520 Pope Leo X issued the papal bull Exsurge Domine that threatened Luther and Karlstadt with excommunication, and condemned several of their theses. Both reformers remained steadfast, and excommunication followed in 1521 in the papal bull Decet Romanum Pontificem. After the Diet of Worms (January–May, 1521), and while Luther was hiding at Wartburg Castle, Karlstadt worked toward reform in Wittenberg. On Christmas Day 1521, he performed the first reformed communion service. He did not elevate the elements of communion, wore secular clothing during the service, and purged all references to sacrifice from the traditional Mass. He shouted rather than whispered the words of institution ("This is my body....", etc.) in German instead of Latin, rejected confession as a prerequisite for communion, and let the communicants take both bread and wine on their own during the Communion. In early January 1522, the Wittenberg city council authorized the removal of imagery from churches and affirmed the changes introduced by Karlstadt on Christmas. Karlstadt wrote his thesis "On the Removal of Images and That There Should Be No Beggars Among Christians" in 1522, shortly after this authorization from the city council. On 19 January Karlstadt married Anna von Mochau, the fifteen-year-old daughter of a poor nobleman. On 20 January the imperial government and the Pope ordered Frederick the Wise, Elector of Saxony to undo the changes. Frederick let most of the Mass revert to its Catholic form, but in a letter to the Wittenberg Council, he noted his personal compassion for Karlstadt. Relationship with Luther In the first week of March, Luther returned from Wartburg. From 9–16 March Luther gave eight sermons in which he stressed some theological similarities with Karlstadt, but, in hindsight, urged caution. This was a major turning point between Karlstadt and Luther. Karlstadt reasserted some of his moderately mystical leanings, continued wearing peasants' clothing, asked to be called "Brother Andreas," and became disillusioned with academic life. In fact, he renounced his three doctoral degrees, and, according to one source, "gave excellent but infrequent lectures." In May 1523, Karlstadt was invited by the church of Orlamünde to be its pastor, and he accepted at once. Here he instituted all his radical reforms, and Orlamünde became the model of a congregationalist reformation.