An indulgence was a pass that you bought to forgive your sins. The church sold those and took advantage of people. People would take advantage of those passes and buy many of them and then not care if they sinned. People were under the impression that they could buy their way into heaven. Johann Tetzel started to sell them because he wanted to raise money to rebuild St. Peter’s cathedral in Rome. The Church’s use of the Indulgence was against many of their principals.