In 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.
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.
[3] The long informative captions in the maps of Ortelius' 16th-century atlas, Cartographia Neerlandica, offer some detail about this Apennine Sybil: The Mountain Apennine here looms over the country with exceedingly high cragged tops, in which one finds that huge cave called Sibylla's cave, (in their language Grotta della Sibylla) and which the poets would have the Elysian Fields.
For the common people dream about a certain Sibylla [supposed] to be in this cave, who [is claimed to] possess a large kingdom full of gorgeous buildings and Princely palaces, covered with pleasant gardens, abounding with many fine lecherous wenches and all kinds of pleasures and delights.
And after they have been there for the period of one whole year, they have the freedom and liberty given to them by Sibylla to depart (if they please) and from that moment, having returned to us, they state that they live a most blessed and happy life ever after.