Civita Castellana Cathedral

A plaque on the building's exterior commemorates Wolfgang Amadeus Mozart's sojourn in Civita Castellana on 17 July 1770: he also played the cathedral's organ at Mass of that day, a Sunday.

Two central piers support a rounded arch, in which is the writing "Gloria in excelsis Deo...", while another inscription at the top contains the name of the portico's designer, "IACOBUS CIVIS ROMANUS" ("James, citizen of Rome") and the date of execution (1210).

In the transept's arms are two monumental Baroque altars: the right one is dedicated to the Madonna of the Light, and incorporates an 11th-century fresco; the left-hand altar is dedicated to the Madonna of the Rosary, and has a 16th-century canvas surrounded by 15 panels, depicting the mystery of the rosary.

A door on the left side of the presbytery leads to the oratory of the Heart of the Virgin Mary , built as a chapel in the 14th century.

This houses important medieval works including: Under the presbytery is the crypt, with cross-vaults, dating to the 12th century but renewed later.