In Greek mythology, Oceanus (Okeanos) is one of the Titans, son of Uranus and Gaia, and the god of the great world-encircling river. Brother-husband of Tethys, he is father of the river gods and the Oceanids. Unlike most Titans he usually stands apart from the castration of Uranus and the Titanomachy. This entry is the mythic river-Titan — not the modern Atlantic Ocean alone, though later geography reused his name.
Adapted from Wikipedia, "Oceanus" · CC BY-SA 4.0
I.Family and cosmography
Hesiod lists Oceanus as the eldest Titan and husband of Tethys. By her he fathers three thousand river gods (Acheloüs, Alpheus, Scamander, and many others) and three thousand Oceanids (among them Metis, Eurynome, Doris, Clymene, Perseis, Idyia, and Styx). As a place he is the "perfect," "backflowing" river that bounds the earth, source of all rivers, springs, and — in Homer — every sea.
Homeric lines that call Oceanus "genesis of the gods" and Tethys "mother" have been read as traces of a theogony in which the pair, rather than Uranus and Gaia, are primeval parents. Plato's Timaeus offers a mediating stemma: Uranus and Gaia beget Oceanus and Tethys, who in turn beget Cronus, Rhea, and the other Titans.
II.Mythology
In Hesiod, Oceanus does not join Cronus's attack on Uranus; Apollodorus has all Titans except Oceanus take part. He likewise seems to stay out of the Titanomachy: he sends Styx and her children to Zeus's side, and Hera recalls being fostered by Oceanus and Tethys during the war. Afterward he remains free while other Titans are confined in Tartarus.
In Aeschylus's Prometheus Bound he visits the enchained Prometheus on a winged steed, urging humility before Zeus. Pherecydes tells that Oceanus once raised waves against Heracles crossing in Helios's cup, then desisted when the hero threatened him with his bow.
III.Iconography and later reception
Early Attic black-figure shows him horned, part fish, among the gods at the wedding of Peleus and Thetis. Hellenistic and Roman mosaics favour a muscular bearded upper body with crab-claw horns and a serpentine lower body. He fights among the gods on the Pergamon Altar Gigantomachy.
As Greek geography improved, "Ocean" increasingly meant the outer Atlantic while Poseidon ruled the Mediterranean. Herodotus already doubted a physical river called Ocean. This notice treats the Titan and mythic world-river, not later oceanography alone.