original question: How many art subjects are there of the [Crucifixion]?
answer: 2
answer type: Art Subject.
auxiliary information: The Crucifixion is the subject of three different paintings by the Italian Renaissance master Antonello da Messina; the first two were completed around 1454/1455, the third in 1475. They are housed in the Brukenthal National Museum; the Royal Museum of Fine Arts of Antwerp and in the National Gallery, respectively.
Can you tell me how what number of art subjects there are of the [Crucifixion]?