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 had been suffering from ill health for years, including Ménière's disease, vertigo, fainting, tinnitus, and a cataract in one eye. From 1531 to 1546, his health deteriorated further. The years of struggle with Rome, the antagonisms with and among his fellow reformers, and the scandal which ensued from the bigamy of the Philip of Hesse incident, in which Luther had played a leading role, all may have contributed. In 1536, he began to suffer from kidney and bladder stones, and arthritis, and an ear infection ruptured an ear drum. In December 1544, he began to feel the effects of angina.

Question:
What did Luther begin to experience in 1536?

kidney and bladder stones