Commissioned by the Confraternity of S. Caterina and completed in 1726, in the place where tradition places the birthplace of S. Rosalia, whose name was then transmitted to a well, in the garden of the oratory. In the entrance vestibule there is a painting by Giuseppe Salerno, known as the Zoppo di Gangi, with the “Marriage of St. Catherine”.
The elegant and prestigious decoration makes the interior a significant example of the inspiration and skill of the decorators, who managed to transform a simple wall casing into a delightful casket of plastic movements: cherubs, friezes and gilded stuccos are mixed with reliefs and statues in the round. The decoration was made by Giacomo Serpotta and, subsequently, by his son Procopio.
On the entrance, under the graceful triple arched choir, are the statues of “Wisdom” and “Science”; allegories of the sciences on the walls. In the rectangular reliefs, under the windows and in the choir, episodes from the life of St. Catherine are narrated. On the altar the canvas with the “Martyrdom of St. Catherine” from 1609 is the work of Giuseppe Salerno. On the entrance wall is the “Virgin and Child” by Raphaelite Vincenzo da Pavia. Along the sides are the seats of the brothers in wood painted with stories from the life of the Saint. Since 1946, the oratory has housed the Order of the Holy Sepulcher.