In 1818, an unnamed author pillages an archaeological site on the Bay of Naples of written artifacts—authentic Sibylline prophecies—that she’ll later transcribe. What results, is the futuristic story in the reader’s hands.
The visit to Baiae in 1818 was real; and Mary and Percy Shelley, definitely, had they found any artifacts lying around, prophetic or otherwise, would have taken them just the same as the fiction details.
These were the same shores described a hundred years later by Elizabeth Hazelton Haight, a classical scholar who taught at Vassar College, in a beautifully rendered snapshot of the ancient world:
A few examples of Cumaean pottery, from a 1913 study on-line at Heidelberg University:
And here’s what the entrance to the Sibyl’s cave looked like back then:
The place had been a vacation spot in more recent centuries past, as indicated by the drowned Roman villas leading up to those “radiant promontories” (a fragment of Mary Shelley’s Introduction that I was sorry not to find a place for). At our own 100-year mark, this resort aspect of Baiae was covered in a lovely and adroit study (with irresistible illustrations) by Lien Foubert, a Dutch ancient historian, in the Mediterranean Historical Review.
Lucky travelers today get to leave the boat and do some scuba diving. Here you can explore the Underwater Archaeology Park Of Baiae on-line.