Even Catholics admit that Tetzel's writings penned the tune:
What beggars the belief is that a lone monk could have instituted such a policy. Please remember that Luther's 95 Theses was addressed the issue of indulgences and provided an opportunity for the Church to renounce the practice. They never did until about 100 years later.
Tetzel, on the other hand, who was this poor misguided monk received full burial honors by the Church.
Hint: NOT from hell.