The Diocesan Museum picture gallery is spread over two floors. The lower floor houses older paintings from the 15th-16th centuries, while the upper floor houses 17th and18th- century paintings on canvas.
On the lower floor it is possible to immediately admire the majestic polyptych by Fra Marino Angeli, dating from around the mid-15th century and from the parish of San Procolo di Collina, now an outlying hamlet of Monte Vidon Combatte. The figures include the Madonna and Child Enthroned with Angels, the Pietà, Saints Anthony Abbot and Maron, and Saint Sebastian and Saint Agatha. Fra Marino Angeli, a populariser of courtly Gothic art, was a Farfa monk from Santa Vittoria in Matenano, whose activity is documented from 1437 to 1462. He enjoyed high regard, having attended the school of the most illustrious masters of the time.
Two other works of great beauty are the panels by Vittore Crivelli, a Madonna and Child and another Pietà, which were once part of the polyptych of San Giuliano, but were later fragmented.
Vittore, brother of the more famous Carlo, was born in Venice around 1440. He arrived in the Marche at the age of forty and set up home in the town of Fermo, bringing his art and works to the surrounding area. His sumptuous decorative style focused on certain elements that are particularly evident in The Madonna with Child, the splendid central panel of the polyptych. In it the gilded robes, bas-reliefs obtained from plaster and presence of flowers and fruit are evident, starting with the festoon, a decorative element, but also a strongly symbolic one, that tops the work of Paduan origin.
Climbing to the upper floor, the art gallery boasts works attributed to Carlo Maratta, Corrado Giaquinto, Pomarancio and Hayez.