The National Mythology Exam is over, but here is one last word on the subject. The word stygian is an adjective  that means dark or gloomy. It is related to the River Styx, the main river of the Underworld, ruled by Hades.  Spirits must cross this river in order to enter the realm of the dead. Charon, the ferryman, would provide a boat ride across the river, only if the spirits could pay him. Ancient Greeks used to put a coin under a deceased person’s tongue to pay for the boat ride. If the spirits couldn’t pay, they would wander the banks of the Styx forever. The most solemn oath the gods could make was to swear by the River Styx. The four other rivers are, the Lethe, Phlegethon, Acheron, and the Cocytus. I’ve written about the River Lethe in a previous post.