Sibyls were women from the ancient era who could foretell the future. They were named for their region of origin. So, for example, the Delphic Sibyl was from Delphi, the Libyan Sibyl from Libya, and so on. The Romans identified 10 sibyls in their writings, each associated with an oracular shrine where they obtained the information that allowed them to declare their prophecies, like the Persian Sibyl who foretold Alexander the Great's successes in battle while presiding over the Oracle of Apollo in Babylon. The Early Christian leaders interpreted the prophecies of the sibyls as announcements of the coming of Christ. As a result, sibyls were commonly depicted in religious art. The best-known representations of these women are in Michelangelo's Sistine ceiling at the Vatican (1508-1512). Jan van Eyck included sibyls and prophets, their male counterparts, on the lunettes of the Ghent Altarpiece (c. 1425-1432; Ghent, Cathedral of St-Bavon) above the Annunciation. Andrea del Castagno added the Cumean Sibyl to the group of illustrious men and women he painted in the loggia of the Villa Carducci at Legnaia (1448; now in Florence, Uffizi), Raphael rendered five sibyls above an arch in the Chigi Chapel at Santa Maria della Pace, Rome (1512-1513), and Domenichino painted an unidentified sibyl (1616-1617; Rome, Galleria Borghese) as a single figure surrounded by musical instruments, as supposedly these women imparted their prophecies through song.
Historical dictionary of Renaissance art. Lilian H. Zirpolo. 2008.