Perses (brother of Aeetes)
In Greek mythology, Perses is the brother of Aeëtes, Aloeus, Circe and Pasiphaë, as he is a son of Helios, the god of the sun, by Perse, an Oceanid nymph.
Unlike his siblings, Perses was not mentioned in earlier sources like Hesiod's Theogony nor Apollonius Rhodius' Argonautica. Rather, most of the sources mentioning him are Roman.
In Valerius Flaccus' Argonautica, Perses is a brother of Aeëtes only on his mother's side, his father being unknown.
Etymology
His name is connected to either the Ancient Greek word perthō, or from the word for Persian, from Ancient Greek 'Persís' Περσίς.Mythology
Perses' brother Aeëtes had been warned by an oracle that great peril would come to him if the Golden Fleece was ever removed from Colchis. Indeed, after Medea helped Jason steal the fleece, Perses usurped the throne of Colchis from his brother, but was subsequently slain by Medea, his paternal niece, who restored her father to the throne, as an oracle had once predicted that he would be slain by his own kin.One tale goes that after Perses seized power, Medea's son by either Aegeus or Jason, Medus, arrived in Colchis and was imprisoned immediately, though under a false identity. Soon after a famine broke out. Medea arrived in Colchis too, claiming to be a priestess of Artemis, and unknowingly, betrayed her son's true identity to Perses. Medea, under the pretext of simply wanting to talk to him, secretly gave Medus a sword, and explained what had happened to his grandfather Aeëtes. Medus then slew Perses.
Although distinct from the Titan known as Perses, who is known for fathering Hecate, the goddess of witchcraft, Diodorus Siculus in his Bibliotheca historica made this Perses the father of a witch priestess sharing some traits and the name of this goddess, by an unknown mother; Perses' brother Aeëtes then married this Hecate and had Medea and Circe by her. Diodorus describes Perses as "exceedingly cruel" and "lawless".