At one time this myth would have been expanded into a preface to Book II Jason Triumphant, but since then I have decided not to do so. The reasons were the length of the treatment I wished to provide and because it necessitates a fantastical representation, whereas I want to focus on the historical, human aspects of the myths and leave fantasy outside of the books. I could take the approach of the ancient mythographer Diodorus Siculus, by seeking a plausible explanation of the myth, but I feel that diminishes the story.
The most traditional version of the myth, which I intended to follow, has Phrixus and his twin-sister Helle - the children of Athamas and the demi-goddess Nephele - as victims of their step-mother Ino's jealousy. One episode has Ino, a daughter of Cadmus the founder of Thebes, plotting to murder her step-children. She prepares the children for bed, placing golden crowns on Phrixus and Helle, but no crowns on her own children, Learchus and Melicertes. However, their nursemaid places the crowns on Ino's own children, and in the dark she mistakenly slaughters her own children.
The most famous episode then follows, when a famine strikes the kingdom. Athamas sends messengers to the Oracle at Delphi to enquire how the famine may be lifted. But Ino bribes the messengers to lay the blame on Phrixus and Helle, demanding that they be sacrificed. Athamas reluctantly obeys, but at the moment they are due to be sacrificed a winged golden ram appears, sent by their mother, and carries them eastwards. As they pass over the straits between Asia and Thrace, Helle loses her hold, falls into the sea and drowns, giving her name to the straits - the Hellespont. On his arrival in Colchis, Phrixus sacrifices the ram to Poseidon and offers the fleece to Aeëtes. The ram is honoured by being raised into the heavens as the constellation Aries.
Diodorus Siculus' version is more bland, with Phrixus and Helle carried eastwards on a ship and Helle falls overboard in the midst of a bout of sea-sickness. Phrixus' attendant Crius (whose name means "Ram") is captured in Colchis, sacrificed by Aeëtes and flayed. His skin is painted gold and nailed to the Temple of Ares, and this becomes the Golden Fleece. Understandably I would rather not use this watered down version of the myth.