Monte Vettore is a mountain on the border between Umbria and the Marche, in central Italy. It is part of the Sibillini Mountains range and lies in the Parco Nazionale dei Monti Sibillini. Today climbers reach it from the Umbrian side from Norcia, or, on the Marche side, from Ascoli Piceno. Below the peak, in a small enclosed valley is one lake called the Lago di Pilato, at an altitude of 1,940 metres, where, according to the local medieval legend, the body of a remorseful Pontius Pilate was buried in the waters. A similar legend is told of Pilatus in Switzerland.
The local medieval tradition was that the Apennine Sibyl, a mysterious prophetess not counted among the Sibyls of Classical Antiquity, was condemned by God to dwell in a mountain cavern and await Judgement Day, having rebelled at the news that she had not been chosen Mother of God, but that some humble Judaean virgin had been favored. The peak of Monte Vettore, surrounded by reddish cliffs was recognized as the crown of Regina Sibilla.
Less stringently Christian legend set her in an underworld paradise entered through a grotto in the mountains of Norcia. Nearby the magical lake is fed by water from the cavern. Whoever stayed longer than a year could no longer leave, but remained deathless and ageless, feasting in abundance, amid revelry and voluptuous delights.
In the romance of Il Guerrin Meschino, written by Andrea da Barberino about 1410, the central episode of the sixth part (Canto V) contains the "prodigious adventures" of Guerrino with this enchantress, the "Fata" Alcina, whom he seeks out, against all advice. He locates her cavern in the mountains of central Italy with the aid of Macco, a speaking serpent. She shows him the delights and horrors of her cavern, where sinners have been changed to the appropriate animals, but where sin is the only path to the knowledge of his real parents that he seeks, and Guerrin has to flee.