This cathedral was built in 11C, then completely remodelled in the 17C. Its façade, which was completed in 1906 has a portal set into it decorated with a 16C low-relief depicting Roger I on horseback flattening a muslim! The interior which is quite superb, has frescoes in trompe-l'oeil immitating scroll, loop and putti shaped stuccos, gives the sanctuary a theatrical feel. It is decorated by a group of the Transfiguration by A. Gagini, placed on sur un majetueux plinth Renaissance.