Phrixus and Helle were the children of Athamas and Nephele. Phrixus travelled with Helle on a miraculous ram to Colchis, and although Helle fell off (into what became the Hellespont), he stayed on. When he reached his destination the ram asked him to sacrifice it. Phrixus did so and hung its golden fleece on an oak in the grove sacred to Ares.

This was the Golden Fleece that became the object of the voyage of the Argonauts. Phrixus has a name that derives from phrix, 'bristling', in turn from phrissa, 'to bristle' (of hair or a mane). This could mean 'bristling with horror' but it seems much more logical to apply it to the Golden Fleece and see it as a 'ruffling' of the rich coat of the ram.