Oceanus

In classical antiquity, Oceanus (from Greek: Ὠκεανός, lit. "ocean") was believed to be the world-ocean, which the ancient Romans and Greeks considered to be an enormous river encircling the world. Strictly speaking, Oceanus was the ocean-stream at the Equator in which floated the habitable hemisphere (oikoumene οἰκουμένη). In Greek mythology, this world-ocean was personified as a Titan, a son of Uranus and Gaia. In Hellenistic and Roman mosaics, this Titan was often depicted as having the upper body of a muscular man with a long beard and horns (often represented as the claws of a crab) and the lower body of a serpent (cf. Typhon). On a fragmentary archaic vessel of circa 580 BC (British Museum 1971.11-1.1), among the gods arriving at the wedding of Peleus and the sea-nymph Thetis, is a fish-tailed Oceanus, with a fish in one hand and a serpent in the other, gifts of bounty and prophecy. In Roman mosaics, such as that from Bardo (illustration below) he might carry a steering-oar and cradle a ship.

Oceanus appears in Hellenic cosmography as well as myth. Cartographers continued to represent the encircling equatorial stream much as it had appeared on Achilles' shield.

Though Herodotus was skeptical about the physical existence of Oceanus, he rejected snowmelt as a cause of the annual flood of the Nile river; according to his translator and interpreter, Livio Catullo Stecchini, he left unsettled the question of an equatorial Nile, since the geography of Sub-Saharan Africa was unknown to him.