Over the entrance to the Temple of Apollo at Delphi were carved two short commands: "Know thyself" and "Nothing in excess." Inside, for well over a thousand years, a priestess called the Pythia sat on a bronze tripod above a cleft in the rock and delivered the god's answers to kings and commoners. Ancient writers said she breathed vapors rising from the ground before she spoke. For centuries modern scholars dismissed the story, until geologists in the early 2000s found two faults crossing beneath the temple and proposed that gases seeping from them could have produced a trance-like state.
So what is a pagan prophetess doing on the ceiling of the Pope's private chapel? When Michelangelo painted the Sistine ceiling between 1508 and 1512, he set five sibyls alongside seven Hebrew prophets. Christian tradition held that certain sibyls, the prophetesses of the ancient world, had foretold the coming of Christ, and collections of "Sibylline Oracles" circulated that seemed to prove it. Including them was a way of saying that the whole ancient world, not just Israel, had been waiting for the Messiah. The medieval hymn Dies Irae, sung at funeral masses, even names the sibyl beside King David as a witness to the Last Judgment.
Michelangelo's Delphic Sibyl is the youngest and perhaps the most beautiful of the five, and the most startled. She seems to have just heard something, caught at the instant a prophecy arrives.
Giorgio Ghisi, an engraver from Mantua, copied her around 1570 to 1575 as part of a series of the prophets and sibyls of the Sistine Chapel. In an age before photography, prints like this were how most people outside Rome ever saw Michelangelo's work. Artists across Europe studied them, and collectors bought them as the next best thing to standing under the ceiling. Ghisi was one of the finest engravers of his generation, known for translating complex paintings into rich networks of lines while keeping their sculptural weight.
There's a nice irony in the chain of transmission. The Pythia spoke the god's words, which priests then turned into verse. Michelangelo turned the prophetess into paint, and Ghisi turned the painting into lines of ink on paper that traveled farther than either of them. Every step is an act of interpretation, which is exactly what oracles always required.
Her message, whatever it was, still feels addressed to us. Of all the words connected with Delphi, the one that survived best is the simplest: know thyself. It's a fine thing to have looking down from a wall.
Ghisi's The Delphic Sibyl appears on our: