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:
The enforcement of the ban on the 95 Theses fell to the secular authorities. On 18 April 1521, Luther appeared as ordered before the Diet of Worms. This was a general assembly of the estates of the Holy Roman Empire that took place in Worms, a town on the Rhine. It was conducted from 28 January to 25 May 1521, with Emperor Charles V presiding. Prince Frederick III, Elector of Saxony, obtained a safe conduct for Luther to and from the meeting.

Question:
When did Luther appeared before the Diet of Worms?

18 April 1521