It is dedicated to the martyrs Saints whose relics are preserved under the central altar. The current Gothic Cathedral, whose construction began in the late twelfth century, is built on the site of the previous thousand years Cathedral. Completed in its essential forms in 1241, it underwent alterations during the sixteenth and eighteenth century restoration work carried out between 1913 and 1918 have restored the original look internally. The facade has a pointed doorway, on which is a large window surrounded by five bas-reliefs of the thirteenth century, depicting the symbols of the four evangelists. Inside, the Church has a single nave with a rectangular apse, beamed ceiling and ten pointed arches that support the roof. The restoration work led to the discovery of a Gothic tomb, with two stone statues depicting the Saints and a Roman sarcophagus containing the relics of Saints holders. Above the altar is an important wooden crucifix of the thirteenth century. There are several side chapels with numerous works of art, including those of Benedict and Virginio Nucci. It's recent work (Augusto Stoppoloni, 1916-1918), the decoration of the apse and the triumphal arch. The pavement dates back to the sixteenth century.