Places
The River Styx
STIKS
The river the gods swear by, where an oath broken costs a god nine years of silence.
Styx is a river and also a person — an Oceanid, the eldest daughter of Ocean, who brought her children to fight for Zeus against the Titans before anyone else committed. Her children are Zelus, Nike, Kratos and Bia: rivalry, victory, strength and force. Zeus rewarded her by making her name the binding term of every divine oath.
The mechanism is specific. A god swearing by the water of Styx and breaking that oath lies breathless for a year, then is exiled from the councils and feasts of the gods for nine more. It is the only enforceable contract in a pantheon of beings who otherwise do as they please, and it exists because Styx picked a side early.
As a river it bounds the Underworld, and Charon ferries the dead across it. In later tradition it is where Thetis dipped Achilles to make him invulnerable — a detail Homer does not have, but which has become the best-known thing about the water.
The Greeks located an earthly Styx too: a waterfall in Arcadia, its water reputed to be so corrosive it would dissolve any vessel but one made of horse's hoof. Whether that reputation caused the myth or the myth caused the reputation is not recoverable.
Styx's children are the giveaway about what the oath really is. Zelus, Nike, Kratos and Bia — rivalry, victory, strength and force — stand permanently beside Zeus's throne in Hesiod. The god who governs by power keeps power's four aspects at his shoulder, and swears by their mother. The most binding promise in the pantheon is secured by the family that enforces it.
Gods involved
The River Styx: common questions
Why do the gods swear on the River Styx?
Because Styx sided with Zeus against the Titans before the outcome was clear, and he made her name the binding oath as a reward. Breaking it costs a god a year breathless and nine years exiled.
Which god is your parent?
Twelve questions and the campfire decides.