was a celebrated astrologer at Rhodes, with whom Tiberius became acquainted during his residence in that island. and ever afterwards held in the highest honour. It was said that Tiberius had intended to kill him after consulting him respecting his future destinies; but that Thrasyllus, when he had predicted the empire to Tiberius, said that he perceived from the observation of the stars that his own death was near at hand, by which announcement he so convinced Tiberius of the truth of his art, that Tiberius not only gave up his intention of murdering him, but adimitted him to his intimate friendship. Thrasyllus accompanied Tiberius to Rome, when he was recalled by Augustus, and appears to have always lived with him. He died in A. D. 36, the year before Tiberius, and is said to have saved the lives of many persons whom Tiberius would otherwise have put to death by falsely predicting for this very purpose that the emperor would live ten years longer. (Tac. Ann. 6.20-22; Dio Cass. lv ll, 57.15, 58.27; Suet. Ang. 98, Tib. 14, 62, Cal. 19 ; Schol. ad Juv. 6.576; Julian. Ep. ad Themist. p. 265. Spanh.) The son of this Thrasyllus succeeded to his father's skill, and is said to have predicted the empire to Nero. (Tac. Ann. 6.22, comp. 14.9; D. C. 61.2.)
A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890