The Diocesan Museum of Fermo is located in the historic center of the city next to the Metropolitan Cathedral Basilica. The museum was opened in 2004 and has been strongly supported and followed in its implementation by the Archbishop Mons. Cletus Bellucci. Of great interest is the Treasure Room, so named because it retains the most valuable objects of the Treasury of the Cathedral and is the first of the Diocesan Museum room. Here we find the beautiful missal de Firmonibus, an illuminated manuscript by Giovanni Ugolino from Milan in 1436 commissioned by Giovanni De Firmonibus from which it takes its name. This code, extraordinary example of Gothic art, contains initial thirty-illuminated, decorated or stained, two pages with large friezes and marginal miniatures, two full-page illustrations. The most popular page is definitely one of the Ride, which depicted the historical parade in honor of the Assumption. the Stauroteca, a reliquary cross donated by Francesco Todeschini Piccolomini, future Pope Pius III, in 1503, surely its realization is much older and Venetian manufacture, for decoration filigree. In the terminations of the arms are inserted representatives thumbnails on the recto the protagonists of the Crucifixion, on to the symbols of the Evangelists.