Styx

In Greek mythology, the river surrounding Hades, the underworld. When an oath was sworn by Styx, its waters were taken to seal the promise. Gods who broke such a vow suffered a year's unconsciousness and nine years' exile, while to mortal transgressors its waters were deadly poison. The tradition may have derived from some form of trial by ordeal.

The river was believed to rise in the mountains near Nonacris, in northern Arcadia, and fell 185 m/605 ft down a sheer rockface into a ravine to reach its subterranean course. The nymph of Styx lived at the entrance to Hades, in a grotto supported by silver columns. She was the mother of Nike, goddess of victory.