Martin Luther, the Protestant Reformer wrote his 95 Thesis to protest the corruption of Johann Tetzel and the way he collected indulgences for the Papacy. Indulgences are basically money. It's the same as giving alms into the Roman Catholic Church. Tetzel even went as far as to tell people that they could pay off future sins by giving an indulgence. One of the corrupt results of this practice was that people thought that they didn't have to repent of their sins or even feel bad about them.