The Diocesan Museum, situated inside the Archbishopric, was established in the late 1960s to house and display the historical and artistic heritage of the Archdiocese of Spoleto-Norcia. Exhibits hang in chronological order in the palace reception rooms known as the "Cardinal's Apartment", which were frescoed from the second half of the 16^th century.

Several masterpieces acquaint visitors with local and "foreign" schools of art stretching from the earliest times to the Renaissance and the age of Baroque, with work by masters from Spoleto, Florence and Rome including the Master of the Blue Cross, the Master of San Felice di Giano, Neri di Bicci, Filippino Lippi, Domenico Beccafumi, the Cavalier d'Arpino and Gian Lorenzo Bernini.