Obscure they went, thro' dreary shades, that led
Along the waste dominions of the dead
Thus wander travellers in the woods by night,
By the moon's doubtful and malignant light,
When Jove in dusky clouds involves the skies,
And the faint crescent shoots by fits before their eyes...
Aeneas descends with the help of the Cumaean Sibyl, and it is her successor who reveals to Graves's Claudius his own destiny.
The cave itself was discovered by Italian archaeologists in 1932.