The patron saint of Guardialfiera is Saint Gaudentius, celebrated on 1 and 2 June. On 7 April 1751 his relics were carried by two Capuchin friars from the catacombs of Priscilla, in Rome, to the cathedral of Guardialfiera, and given to Monsignor Pasquale Zaini, then bishop of the city, by Pope Benedict XIV: the remains are still visible today in the cathedral of Santa Maria dell'Assunta and are carried in procession during the patronal feast.
It is unclear whether the present cathedral structure already existed at the time of Pope Leo IX's visit in 1053, but the diocesan registers of the time record that the church was raised to cathedral status in 1061, presided over by a bishop named Pietro. After the 1456 earthquake it was rebuilt, and in 1460 Bishop Jacopo added the Holy Door, one of the few existing outside Rome: it is opened once a year during the feast of Saint Gaudentius, except in jubilee years, when it is Rome's own Holy Doors that remain open. In 1975 a medieval crypt was discovered during restoration works on the cathedral.
