Bagoas was a eunuch who later became the vizier to Artaxerxes III. In this role, he allied himself with the Rhodian mercenary general Mentor, and with his help succeeded in once again making Egypt a province of the Persian Empire (probably from 342 BC). Mentor became general of the maritime provinces, suppressed the rebels in Egypt and sent Greek mercenaries to the king, while Bagoas administered the satrapies and gained such power that he was almost the real master of the Persian Empire towards the end of Artaxerxes III's reign (Diod. xvi. 50; cf. Didymus, Comm. in Demosth. Phil. vi. 5).
Artaxerxes IV Arses was the youngest son of King Artaxerxes III and Atossa and was not expected to succeed to the throne of Persia. His unexpected rise to the throne came in 338 BC as a result of the murder of his father and most of his family by Bagoas, when the vizier fell out of favour with Artaxerxes III. Bagoas sought to remain in office by replacing Artaxerxes with his son Arses (Artaxerxes IV), whom he thought easier to control. Arses remained little more than a puppet-king during the two years of his reign while Bagoas acted as the power behind the throne. Eventually, disgruntled by this state of affairs and possibly influenced by the nobles of the Royal Court, who generally held Bagoas in contempt, Arses started planning Bagoas' murder. However, Bagoas again acted first in order to protect himself and managed to poison and kill Arses. Bagoas then raised a cousin of Arses to the throne as King Darius III of Persia.
In 338 BC Artaxerxes III was according to a Greek source, Diodorus of Sicily, poisoned by Bagoas with the assistance of a physician.  A cuneiform tablet in the British Museum (BM 71537) however suggests Artaxerxes III died from natural causes.
When Darius attempted to become independent of the powerful vizier, Bagoas tried to poison him too; but Darius was warned and forced Bagoas to drink the poison himself (Diod. xvii. 5; Johann. Antioch, p. 38, 39 ed. Müller; Arrian ii. 14. 5; Curt. vi. 4. 10).
According to the Bibliotheca historica by Diodorus Siculus, Bagoas became very wealthy by confiscating the sacred writings of the Egyptian temples and giving them back to the priests for large bribes (Diod. XVI. 51). When the high priest of Jerusalem murdered his brother Jesus in the temple, Bagoas (who had supported Jesus) put a new tax on the Jews and entered the temple, saying that he was purer than the murderer who performed the priestly office (Joseph. Ant. xi. 7.1).
Bagoas' house in Susa, with rich treasures, was presented by Alexander to Parmenion (Plut. Alex. 39); his gardens in Babylon, with the best species of palms, are mentioned by Theophrastus (Hist. Plant, ii. 6; Plin. Nat. Hist. xiii. 41).
- Bagoas is featured as a character in the ancient novel Aethiopica, by Heliodorus. In the novel, he is portrayed as a trusty eunuch servant of the Persian satrap of Memphis. In the course of events, he is captured by the Ethiopian king and assimilated as a servant in the Ethiopian court.
- Bagoas is mentioned in Mary Renault's novel The Persian Boy as the cause of the later Begoas' enslavement and castration.
- Chisholm 1911.
- Briant, Pierre (2002). From Cyrus to Alexander: A history of the Persian Empire. Eienbrauns. p. 769. ISBN 1-57506-120-1.
- Diod. 17.5.3
- "Collection online - Museum number 71537". The British Museum. Retrieved 2017-12-19.
- One or more of the preceding sentences incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). . Encyclopædia Britannica. 3 (11th ed.). Cambridge University Press. p. 202.
- "Elfinspell: Book VIII, Heliodorus - Chariclea's Trial, from Aethiopica by Heliodorus -An Aethiopian Romance, translated by Thomas Underdowne (anno 1587), revised and partly rewritten by F. A. Wright, [with additional corrections in the online edition by S. Rhoads;] 300 AD Greek Novel, prose fiction, adventure and romance, third century Greek Literature, online text, free e-book on Elfinspell.com". www.elfinspell.com. Retrieved 2015-11-04.