In some versions of Greek mythology, Ophion (/oʊˈfaɪən/; Ancient Greek: Ὀφίων "serpent"; gen.: Ὀφίωνος), also called Ophioneus (Ὀφιονεύς) ruled the world with Eurynome before the two of them were cast down by Cronus and Rhea.
Apollonius of Rhodes in his Argonautica (1.495f) summarizes a song of Orpheus: Lycophron (1191) relates that Zeus' mother, Rhea, is skilled in wrestling, having cast the former queen Eurynome into Tartarus.
Ophion is mentioned again by Nonnus (12.43): We also have fragments of the writings of the early philosopher Pherecydes of Syros (6th century B.C.E.
Some fragments of this work mention a birth of Ophioneus and a battle of the gods between Cronus (not Chronos) on one side and Ophioneus and his children on the other in which an agreement is made that whoever pushes the other side into Ogenos will lose, and the winner will hold heaven.
Eusebius of Caesarea in his Praeparatio Evangelica (1.10) cites Philo of Byblos as declaring that Pherecydes took Ophion and the Ophionidae from the Phoenicians.