Built in 1590 by the Compagnia del Rosario established in 1570. From the upper loggia, adorned with marble busts, you pass through a stone portal to the hall that serves as a vestibule; this is decorated with portraits of the Superiors of the Company. The simple rectangular hall with a small gallery was decorated by the masterful hand of Giacomo Serpotta who worked there from 1687 to 1718.
The two entrance doors have portals supported by pairs of atlases; in the upper part of the entrance wall are inserted between draperies, scrolls, plant elements and putti, six reliefs of great perspective force; among these the scene of the “Battle of Lepanto” stands out, placed in the center and performed with great detail. But the entire wall face participates intensely in the sculptural decoration, rendered with vivid effects of decorative realism and the whole participates in the Baroque explosion which here finds its peak: the windows have plastic architectural displays; on the tympanums, on the shelves and on the draperies there are putti and statues; naturalistic elements and festoons come together in a harmonious whole. Under each window there are sculptural paintings with the “Mysteries of the Rosary”.
On the walls are the seats of the brothers in inlaid wood and the floor is in polychrome marble with drawings. On the altar is the canvas of the “Madonna del Rosario” by Carlo Maratta from 1695; on the sides are two eighteenth-century choirs. In addition to the oratory room on the same floor are the premises of the rectory and the small chapel of the Crucifix, called “Oratorio sopra S. Cita”, where in the early 18th century Filippo Tancredi painted the “Adoration of the mystical Lamb on the vault. “.