The cathedral's Roman architecture (12C) has been reworked several times. The aisles are prolonged by vaulted chapels in a half-cupola, like the apse. Not to be missed, in the left aisle, the copy of the Exultet, a precious manuscript of Byzantine origin, written in Beneventine\", Mediaeval writing used in southern Italy. The illumination was placed the back. By mistake? No: the faithful could thus see the pictures whilst the parchment was unrolled for the singers.