You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Martin_Luther

Context:
Luther objected to a saying attributed to Johann Tetzel that "As soon as the coin in the coffer rings, the soul from purgatory (also attested as 'into heaven') springs."

Question:
Who objected to Tetzel's collections of money to free souls from purgatory?

Luther