[2] According to the usual account, Styx was the eldest of the Oceanids, the many daughters of the Titan Oceanus, the great world-encircling river, and his sister-wife, the Titaness Tethys.

[4] She married the Titan Pallas and by him gave birth to the personifications Zelus (Glory, Emulation), Nike (Victory), Kratos (Strength, Dominion), and Bia (Force, Violence).

[5] The geographer Pausanias tells us that, according to Epimenides of Crete, Styx was the mother of the monster Echidna, by an otherwise unknown Perias.

"[15] According to Hesiod, Styx lived at the entrance to Hades, in a cave "propped up to heaven all round with silver pillars".

[16] Hesiod also tells us that Zeus would send Iris, the messenger of the gods, to fetch the "famous cold water" of Styx for the gods to swear by,[17] and describes the punishments which would follow the breaking of such an oath:[18] For whoever of the deathless gods that hold the peaks of snowy Olympus pours a libation of her water and is forsworn, must lie breathless until a full year is completed, and never come near to taste ambrosia and nectar, but lie spiritless and voiceless on a strewn bed: and a heavy trance overshadows him.

[21] Similarly Sol (the Roman equivalent of the Greek Helios) promised his son Phaethon whatever he desired, which also resulted in the boy's death after he asked to drive his father's chariot for a day.

Far under the wide-pathed earth a branch of Oceanus flows through the dark night out of the holy stream, and a tenth part of his water is allotted to her.

[26] So too in Virgil's Aeneid, where the Styx winds nine times around the borders of Hades, and the boatman Charon is in charge of ferrying the dead across it.

[39] However Styx has been most commonly associated with an Arcadian stream and waterfall (the Mavronéri) that runs through a ravine on the North face of mount Chelmos and flows into the Krathis river.

[44] According to James George Frazer, this "fable" provided an explanation for the fact that, from a distance, the waterfall appears black.

[48] According to Plutarch the poisonous water could only be held by an ass's hoof, since all other vessels would "be eaten through by it, owing to its coldness and pungency.

[52] The latter seems to be the case, at least, for the Styx in Apuleius's Metamorphoses, which has Venus, addressing Psyche, give the following description:[53] Do you see that steep mountain-peak standing above the towering cliff?

Dark waves flow down from a black spring on that peak and are enclosed by the reservoir formed by the valley nearby, to water the swamps of Styx and feed the rasping currents of Cocytus.

[56] The other moons of Pluto (Charon, Nix, Hydra, and Kerberos) also have names from Greco-Roman mythology related to the underworld.