On the side wall of the nave, hangs a replica of Raphael’s Transfiguration that was painted by Raphael Sanzio in 1518-1520 and now hangs in Rome at the Pinacoteca Vaticana.
It is described by Richard Stracke, Emeritus Professor of English, Augusta University on https://christianiconography.info/sicily/transfigurationRaphael.html as follows: “Raphael’s great innovation was to elicit the meaning of the Transfiguration by pairing it with the episode that follows in the gospels. While Peter, James, and John are with Jesus on the mountain, a father brings his possessed child to the other disciples. We see them trying unsuccessfully to cure the boy, but after descending from the mountain Jesus will drive the demon out of him. He will then explain to the nine that they failed because of their lack of faith, a charge that is mediated to the viewer by St. Matthew in the foreground with his gospel.”