Bagnoregio is located about 90 km north-west of Rome and about 28 km north of Viterbo. Anciently it was called Novempagi and Balneum Regium, whence the medieval name of Bagnorea.
During the barbarian invasions of Italy, between the 6th and 9th centuries, the city was taken several times by the Ostrogoths and the Lombards.
Charlemagne is said to have included it in the Patrimonium Petri, and the Emperor Louis I to have added it to the Papal States in 822.