The manner of consulting her is fully described by the Latin poet Virgil in the sixth book of the AEneid.  He tells how AEneas, arriving with his fellow voyagers at the town of Cumae, immediately goes to the temple of Apollo,

    “And seeks the cave of wondrous size,
    The sibyl’s dread retreat,
    The sibyl, whom the Delian seer
    Inspires to see the future clear,
    And fills with frenzy’s heat;
    The grove they enter, and behold
    Above their heads the roof of gold.

* * * * *

    “Within the mountain’s hollow side,
    A cavern stretches high and wide;
    A hundred entries thither lead;
    A hundred voices thence proceed,
    Each uttering forth the sibyl’s rede. 
    The sacred threshold now they trod: 
    ‘Pray for an answer! pray! the god,’
    She cries, ‘the god is nigh!’

    “And as before the door in view
    She stands, her visage pales its hue,
    Her locks dishevelled fly,
    Her breath comes thick, her wild heart glows. 
    Dilating as the madness grows,
    Her form looks larger to the eye;
    Unearthly peals her deep-toned cry,
    As, breathing nearer and more near,
    The god comes rushing on his seer.”

AEneas now begs a favor of the sibyl.  He has heard that here the path leads downward to the dead, and he desires to go thither to visit his father, Anchises.  There are certain conditions to fulfil before setting forth, but when these are done the sibyl guides him on his way, and the journey is safely made.

[Illustration:  THE CUMAEAN SIBYL. Sistine Chapel, Rome.]

Another legend of the Cumaean sibyl has to do with the Roman emperor Tarquin.  The sibyl came to him one day with nine books of oracles, which she wished him to buy.  The price was exorbitant, and the emperor refused her demand.  She then went away, burned three of the books, and, returning with the remaining six, made the same demand.  Again her offer was refused, and again she burned three books and returned, still requiring the original price for the three that were left.  Tarquin now consulted the soothsayers, and, acting upon their advice, bought the books, which were found to contain directions concerning the religion and policy of Rome.

For many years they were held sacred, and were carefully preserved in the temple of Jupiter in the Capitol, under the care of official guardians.  At length the temple was destroyed by fire, and the original sibylline books perished.  In the following centuries they were replaced by scattered papers, collected from time to time in various parts of the empire, purporting to be the writings of the sibyl.  These sibylline leaves, as they were called, contained passages supposed to be prophetic of the coming of Christ, and this is why the Cumaean sibyl is placed by Michelangelo among the prophets.