The construction date of this church is unknown. It seems that it was built on a pre-existing pagan temple. According to archives, Bagnoregio had a bishop in the 600s, so it is very likely that there was a cathedral at the time, perhaps different from the current building. First reliable reports about the existence of the church date back to the second half of the 8th century, but more accurate and official information is dated to the 9th century and mentions enlargements and refurbishments. During Ferdinand of Castile’s bishopric in 1511, architect Nicola Matteucci di Caprarola significantly modified the appearance of the edifice. Apparently, the church had a paleo-Christian portico that was mentioned in 1287 chronicles and in the 1373 statutes. A square-shaped Romanesque bell tower measuring 4m wide and 28 high stands near the Renaissance facade. The church’s interior shows its original form, with a nave and two aisles divided by arcades supported by ancient granite columns. The side walls feature sculpted fragments that testify a 9th-century decorative phase,15th-16th-century refined frescoes on the smaller apses, and numerous valuable altarpieces. Two panels hanging on the right wall respectively portrait a Madonna with St. Dominic and a group of saints constituted by Bonaventure, Francis, and Victoria. The wall includes a Virgin and Child with Saints Thomas, Hildebrand, Bonaventure, and Victoria, and a painting with the Virgin and Saints Bonaventure and Michael. Two shelves support a small marble urn which once contained the remains of Vittoria Romana, the saint martyrized in 251 AD, at the time of Emperor Decius. The relic was moved under St. Peters’s altar in 1782. The history of this cathedral drew to a close with the earthquake occurred on 11 June 1695, when the civil and religious authorities and the majority of the population abandoned the town. Innocence XII transferred the Cathedral from Civita to Bagnoregio on 16 February 1699. Subsequently, St. Nicholas’s Church in Bagnoregio became the new cathedral dedicated to St. Nicholas and St. Donatus.
