"There are many large and diverse rivers, but among this multitude four stand out. The largest of these, flowing the outermost circle, is the one called Oceanus. Opposite to it, flowing in the contrary direction, is Acheron. It flows through desert places and, sinking beneath the earth, arrives at the Acherusian Lake. This is where the souls of most of the dead arrive, and after staying their destined time—some longer, some shorter—they are sent back to be born as living creatures. Between these two a third river issues forth. Near its source, it pours into a huge region burning with much fire and creates a lake larger than our sea, boiling with water and mud. From there it moves in a circle, muddy and murky, coiling around within the earth until it reaches the edge of the Acherusian Lake, though mingling with its waters. After coiling multiple times underground, it pours into a lower part of Tartarus. This river is called Pyriphlegethon, and its fiery streams throw off fragments wherever they reach the surface of the earth. Opposite this, the fourth river falls first into a terrible, wild region which is entirely of an indigo hue, called the Stygian region, and the lake it forms is called the Styx. Plunging into this lake and acquiring terrible powers in its water, the river dips beneath the earth, spiraling opposite to Pyriphlegethon and meeting it at the Acherusian Lake from the contrary side. Its water never mixes with any other, but after circling around, it pours into Tartarus opposite Pyriphlegethon. The name of this river, the poets say, is Cocytus."