Thrasyllus - Astrologer to an Emperor

Tiberius withdrew to the island of Rhodes before returning to Augustus' good graces and being made his heir. Despite the great power he held under Augustus, he felt unappreciated and overshadowed by Gaius and Lucius, the sons of Julia and Agrippa. Tired of his mother's manipulations and his disastrous marriage to Julia, he went into voluntary exile.

The years at Rhodes were disappointing ones for Tiberius. Out of favor at Rome, few called on him. Even the locals were sometimes contemptuous of the prince as evidenced by the refusal of a celebrated scholar to change his lecture schedule to accomodate him. Then he met the man who would change his life - Thrasyllus of Alexandria, the greatest astrologer of the day.

Nota Bene: Don't confuse the position of augur and reading of signs, such as entrails of animals as well as birds, with the astrologers, etc. The augurs were a part of the official State religion and therefore sanctioned.

What information we do have regarding the reality of Tiberius' private life attests to the high regard that he held Thrasyllus. Supposedly, the astrologer had won the future emperor's confidence while on a visit to his villa on Rhodes. In his effort to discover a practitioner upon whose advice he could rely, Tiberius invited one astrologer after another to his villa which sat perched on a cliff overlooking the sea. Apparently the island's reserve of astrologers was dwindling rapidly when Thrasyllus first made his appearance. Tacitus preserves the fullest account of the meeting:

When seeking occult guidance Tiberius would retire to the top of his house, with a single tough, illiterate former slave as confidant. Those astrologers were escorted to him by this man over pathless, precipitous ground; for the house overhung a cliff. Then, on their way down, if they were suspected of unreliability or fraudelence, the ex-slave hurled them into the sea below, so that no betrayer of the secret proceedings should survive.

Thrasyllus, after reaching Tiberius by this steep route, had impressed him, when interrogated, by his intelligent forecasts of future events - including Tiberius' accession. Tiberius then inquired if Thrasyllus had cast his own horoscope. How did it appear for the current year and day? Thrasyllus, after measuring the positions and distances of the stars, hesitated and then showed alarm. The more he looked, the greater his astonishment and fright. Then he cried that a critical and perhaps fatal emergency was upon him. Tiberius clasped him, commending his divination of peril and promising he would escape it. Thrasyllus was admitted among his closest friends; his pronouncements were regarded as oracular. (Annals 6.21)

While the occasion of their meeting was probably not so dramatic, it is known that the emperor was still relying on his pronouncements forty years after they had first met in Rhodes. No other person remained so close to Tiberius for such a long time and the longevity of the relationship was only possible because Thrasyllus never gave his friend reason to doubt his loyalty.

Thrasyllus died in 36 CE, a few months before Tiberius, who expired the following year at age seventy- seven.  We are told that he predicted the exact day and hour of his death.  There is every indication that Thrasyllus remained loyal to Tiberius until the end.  Tradition does indicate that Thrasyllus continued to be held in high regard even long after his death.  His works on a variety of subjects were quoted as authoritative for centuries and Juvenal indicates rather contemptuously, that even in his day, Thrasyllus' writings were a standard for astrological inquiries.

She is an expert herself, giving, not given, advices,

If her husband goes to the wars or returns to his homeland,

She will not be at his side if the runes of Thrasyllus forbids it........

(Satire 6.565-576)

Roman People, Second Edition, Robert B. Kebric, Mayfield Publishing Company, 1993

Chronicle of the Roman Emperors, Chris Scarre, Thames and Hudson, 1995

The Oxford History of the Classical World, John Boardman, Jasper Griffin, Oswyn Murray. Oxford University Press, 1986