 The diocese grew over the centuries, incorporating in 1015 what had been the diocese of Bomarzo.After an earthquake in 1695, the cathedral that had been in Civita di Bagnoregio was replaced by one at Bagnoregio itself.In 1986, the diocese was incorporated into that of Viterbo, by whose bishop it was already administered since the death of the last diocesan bishop of Bagnoregio in 1971.