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:
Johann Eck, speaking on behalf of the Empire as assistant of the Archbishop of Trier, presented Luther with copies of his writings laid out on a table and asked him if the books were his, and whether he stood by their contents. Luther confirmed he was their author, but requested time to think about the answer to the second question. He prayed, consulted friends, and gave his response the next day:

Question:
Who spoke to Luther about his books on behalf of the Empire?

Johann Eck