Three XI-century portals open up in the lower section of the plain façade. The upper section is decorated by a rose window with an arched lintel lavishly decorated with monsters and imaginary creatures. Inside, the church has one nave and two aisles divided by sixteen pillars holding huge arches. The crypt preserves, in the altar, the relics of San Sabino and the icon of the Madonna Odegitria, which, as a probably groundless tradition goes, was taken there in the VII century. Originally, the vestry, or Trulla, may have been a baptistry. The curial palace adjacent to the Cathedral hosts the Diocesan Museum.