Characterized by an irregular polygonal plan that, as a ring, takes place around a large internal courtyard, the Ducal Castle appears as the result of overlapping in time of alterations, renovations and reconstructions. It is accessed through two entrances: a main north-west, stately, introduced by a long cobblestone avenue that allows you to gradually grasp all the grandeur and majesty, and a secondary pedestrian east, which connects it to the heart of the old town and connects it to the adjacent Romanesque Cathedral. The original nucleus consists of the Byzantine knight tower that looks at the Vallo del Cervaro, refounded in the eleventh century by Drogone the Norman; behind it rises the Cassero, military garrison commissioned by Frederick II of Swabia (thirteenth century).
Subsequently, every feudal lord who has succeeded there has adapted the construction to his own needs, giving more and more the appearance of elegant noble residence. In 1563 the castle became the property of Delfina Loffredo, mother of Don Giovanni Guevara, whose descendants lived in the ducal palace until 1961 and gradually transformed it into one of the most beautiful patrician residences in the south. The most important works that gave the building its present appearance date back to the Baroque, when the clock tower was erected, the roof garden was built and the main façade was redefined towards the valley.
Torquato Tasso, Giovan Battista Marino, Maria Teresa of Austria and Pope Benedict XIII found hospitality in the salons with panelled vaults and in the beautiful roof garden.
The Castle houses the Diocesan Museum, the Library of the Community that collects the library of the Guevara and the Diocesan Archive, as well as the Doge’s Residence.