Martin Luther disagreed with Johann Tetzel's preaching that selling indulgences would forgive sins. Because Luther disagreed with these beliefs, he wrote to the Archbishop of Mainz asking him to stop Tetzel from selling indulgences. Luther knew the Pope wanted to sell indulgences to raise money for the Catholic Church to build a new basilica. However, since the Pope was already very rich, Luther argued that he could pay for the church himself without having to sell indulgences to poor people.