Its name derives from “oppidum”, a fortified city, and suggests a certain solemnity that the visitor also finds in a series of architectural structures scattered in the streets, such as the old castle, once known as the “magnum castrum”, built between 1047 and 1051, whose main portal still displays the Orsini coat of arms, the noble palaces and the ancient places of worship, among which the Mother Church of Saints Pietro and Paolo, a treasure chest of artistic jewels such as wooden statues and paintings from the 1600s, and about a kilometre from the town, the Rock church of Sant’Antuono erected on tuff by Basilian monks and preserving a series of frescoes depicting different moments in the life of Christ; starting from the Nativity in the first passage on the left, we retrace moments of his childhood, and then move on to the cycle of the Passion, death and Resurrection housed in the central nave