Thrasyllus was an astrologer and a personal friend of the Roman emperor Tiberius,[4] as mentioned in the Annals by Tacitus and The Twelve Caesars by Suetonius.
Thrasyllus[6] was a Greek Egyptian from unknown origins, as his family and ancestors were contemporaries that lived under the rule of the Ptolemaic Kingdom.
[7] During the reign of the emperor Tiberius, Thrasyllus served as his skilled Court Astrologer both in Rome and, later, in Capri.
[4] As Tiberius held Thrasyllus in the highest honor, he rewarded him for his friendship by giving Roman citizenship to him and his family.
Thrasyllus was an ally[8] who favored Tiberius’ great-nephew Caligula, who was having an affair with his granddaughter, Ennia Thrasylla.
[4] Thrasyllus may have married a member of the royal family of Commagene (whose name is sometimes given as "Aka"), though this has been questioned recently.
In contrast, Thrasyllus and his descendants are presented as power-hungry charlatans in the novel series Romanike.