Although the cathedral was rebuilt in the 16C in a Renaissance style by Piero Lombardo, The façade has preserved a Gothic section as well as some interior elements present before the reconstruction. The high-altar is topped by a Byzantine-Byzantine retable in gilded silver from the 12C. In the right nave, the small Christian museum exhibits precious objects of Lombard art, including the baptistery of the patriarch Callisto and the altar of Duke Rachis.