Answer:
Well this is a tough question so i'll do my best. First back then the pope was considered to be basically God. And the people followed his every movement. So the pope that it was an easier way to get money so he decided to sell these pieces of paper that basically said you are forgiven. So he blessed them and every one wanted them. But if you know what Martin Luther did then it will be easier to understand.
Step-by-step explanation:
Hope this helps