After passing through the beautiful rusticated portal, we enter the former Comital Palace, which was once the residence of the Orsini family. Beyond the wide staircase, we admire, inside the 16th-century cloister, two opposing staircases: one used to reach the episcopal rooms, the other leading to the spaces of the Civic Archaeological Museum.

The Ionic colonnade surrounding the octagonal well, decorated with the counts’ coat of arms, alternates with the richly decorated 15th-century portal at the entrance of the diocesan museum. In 2019, the museum was recognized by the Tuscany Region as a museum of regional significance. It includes a bookshop, a cloakroom, and a small café.

In the entrance hall of the museum, we can see the ceiling fresco of the Triumph of the Orsini, framed by zodiac signs. The entire exhibition complex is spread across more than twenty rooms arranged on three floors, where magnificent sacred artworks in goldsmithing and silverware are displayed like a treasure chest of rare beauty.

Particularly noteworthy are the wooden sculptures, including the life-size statue of the great condottiero Niccolò III Orsini (16th century), preserved in a hall with 15th-century coffered ceilings. In the adjacent room is displayed the statue of the Madonna and Child by Jacopo della Quercia (14th century).

The most important work on display is the predella depicting the Madonna and Child with Saints Peter and Francis, dated 1494, painted in oil on panel by Guidoccio Cozzarelli. Of recent discovery are the frescoes found in the large ground-floor hall. On the ceilings and walls, we can admire depictions of the zodiac, floral motifs, coats of arms, and faces related to the comital family.