The dating of the chapel of San Liborio , is not certain, for some dating to the 11th-12th century, for others a private chapel from the 17th century. It is an autonomous building on the steps leading up to the fortress. The façade, surmounted by a small bell gable, has a granite portal above which, in the center of a broken arch, a round window opens, a source of light for the unadorned interior, with the simple stone altar and the Eighteenth-century stoup in black marble in the shape of a shell.
According to some ancient sources, Liborius was the fourth bishop of Le Mans in France, but it is not possible to trace a precise chronology. His pontificate lasted 49 years, around 380. According to some documents, his successor, Bishop Aldrico, consecrating the cathedral in 835, wanted one of the altars to be dedicated to the saints of Le Mans including Liborio. In 836 the bishop of Paderborn sent a delegation to Le Mans to have the saint’s relics. On the occasion of the translation miracles occurred. San Liborio thus became the patron saint of Paderborn as well. The iconography represents him as an elderly bishop, characterized by the presence of small stones: he is, in fact, the protector of kidney stones. It is also depicted together with a peacock or some peacock feather in memory of the legendary bird that accompanied the translation of the relics. The cult is particularly widespread in France, Germany, Spain and Italy. (Future)