The ancient Romans consulted priests for their daily questions, who "read" the near future in the entrails of sacrificial animals and in the flight of birds. However, the leaders of the Roman Empire believed that only the written guide to the future, the Book of Sibyls, offered absolute certainty. It is believed that the Sibylline Books in their original form were eloquent words of the Greek-speaking prophetess Sibylla, written on oak leaves.

According to legend, the god Apollo gave her a thousand years of life, but because she did not give in to his sexual desires, he withdrew the gift of eternal youth from her, with the result that Sibylla aged steadily over the centuries.

Sibylla offered nine books of prophecy to the seventh and last king of Rome, the tyrannical Lucius Tarquinius the Proud. When Tarquinius refused to buy the books because he thought the money Sibylla demanded was too high, she burned three volumes and offered the rest at the same price. Tarkynios refused the second offer as well, with the result that Sibylla burned three more books.

The king then realized his mistake and agreed to buy the remaining three books at the original price. He took them with him to Rome, where he placed them in a stone treasury in a crypt beneath the new temple of Zeus, built at his command, at Capitol Hill. The care of the books was entrusted to ten, later fifteen, high officials, the guardians of the Sibylline books, who had to keep them in a safe and secret place.

The Sibylline advice

Asking for advice from the books was not the same as asking for an oracle from Pythia at Delphi. Pythian oracles, though ambiguous, answered specific questions. Sibylline books, on the other hand, were written centuries earlier, and the prophecies they contained could be adapted to the present situation.

So when Rome was threatened by an epidemic of plague, the oracle keepers searched the prophecies for the one that best fit the event, interpreted them, and then announced what was to be done to avert the danger. The Guardians never shared the original prophecies, so they could interpret them as they wished. In most of the recorded cases, the books suggested the establishment of religious festivals or the recognition of foreign deities to prevent plagues or other disasters that were predicted. When the Carthaginian general Hannibal threatened Rome, the Guardians turned to the books and offered to bury two Greeks and two Gauls alive in the market. In the end, Hannibal was defeated by the Romans, not because of any divine intervention, but because he did not have enough army and supplies.

Around 83 BC, the Sibylline books were destroyed in a fire, and the Senate sent representatives to collect similar prophecies from temples and shrines throughout the Empire. It has been handed down that the last emperor to consult them was Julian, who was also called "Apostate" because he had tried to restore paganism in the Christianized Roman Empire. Julian consulted them when he was preparing to invade Persia, and his guards replied that the proper year for crossing the frontier was 363 AD. But the books did not specify who would benefit from the Roman invasion of Persian territory. In the end, it turned out that the Persians benefited. The Romans were defeated, Julian was killed, and Christianity was restored to the empire.

The catastrophe

The books, having been replaced after the fire of 83 BC, survived until the time of Theodosius the Great, and survived the destruction of many temples by fanatical Christians, but only for six more years. In 405 AD, the commander of the Western Empire, Stiliko, ordered them to be publicly burned. His motives were political rather than religious, for at that time a barbarian army threatened to use them against the Romans. The books were destroyed, but in the Middle Ages, there were frequent references to another collection of books, the Sibylline Oracles, which supposedly foretold the coming of Christ.