The whole of Parnassos [Mountain in Phokis] is esteemed as sacred [to Apollon], since it has caves and other places that are held in honor and deemed holy. Of these the best known and most beautiful is Korykion, a cave of the Nymphai bearing the same name as that in Kilikia [in Asia Minor]. (9.3.1)
-Strabo, 'Geography'