The cathedral was originally a church practising Orthodox rites prior to the year 1000.

A restoration in the 1970s tried to remove stucco decorations that covered the original Romanesque and Gothic architecture.

The Chapel of the Sacred Heart, once of St Cajetan (Gaetano) had a canvas of the saint attributed to Domenico Antonio Vaccaro.

The church once had a canvas, now stolen, of Santa Lucia by Palma il Giovane.

The apse has an altarpiece of the Assunta, and the chapel of Santa Maria della Sanità has a fresco depicting Saint Catherine of Alexandria.