[1] Cytisorus was the son of Phrixus[2] and Chalciope (Iophassa[3]), daughter of King Aeetes of Colchis.
[6] Cytisorus and his brothers were raised in Colchis, but after their father died, he and his brothers set out to avenge their father’s ill treatment in the hands of king Athamas of Orchomenus and were stranded on Island of Ares (Dia) in the Black Sea until they were rescued from the island by Jason and the Argonauts.
Once Jason discovered that Cytisorus and his brothers were grandsons of King Aeëtes of Colchis, Jason convinced Cytisorus and his brothers to return with him to Colchis and help him to obtain the Golden Fleece.
After the Fleece was retrieved from Colchis, Phrontis and his brothers returned with the Argo's crew to Greece.
[8] In other myths, Sophocles represented Athamas as led to the altar, a victim to the vengeance of Nephele but was saved by Heracles instead.