There are two gates of Sleep: the one is said to be of horn, through it an easy exit is given to true Shades; the other is made of polished ivory, perfect glittering, but through that way the Spirits send false dreams into the world above. And here Anchises, when he is done with words, accompanies the Sibyl and his son together; and he sends them through the gate of ivory.
The mad prophetic Sibyl you shall find, dark in a cave, and on a rock reclin'd. She sings the fates, and, in her frantic fits, The notes and names, inscrib'd, to leafs commits. What she commits to leafs, in order laid, before the cavern's entrance are display'd: many not succeeding, most upbraid the madness of the visionary maid, and with loud curses leave the mystic shade.