The painting depicts the martyrdom of St. Peter. According to ancient and well-known tradition, Peter, when he was condemned to death in Rome, requested to be crucified upside-down because he did not believe that a man is worthy to be killed in the same manner as Jesus Christ.
Michelangelo Merisi da Caravaggio (29 September 1571 – 18 July 1610) was an Italian painter active in Rome for most of his artistic life. During the final four years of his life he moved between Naples, Malta, and Sicily until his death. His paintings combine a realistic observation of the human state, both physical and emotional, with a dramatic use of lighting, which had a formative influence on Baroque painting.