The river Lethe.
Lethe is a river in the Inferno that is known as the River of Forgetfulness and Oblivion.
Description[]
Drinking from the river Lethe ("forgetfulness" or "oblivion") caused complete forgetfulness. Some ancient Greeks believed that souls were made to drink from the river before being reincarnated, so they would not remember their past lives.
The stream of Lethe flows to the center of the earth from its surface, but its headwaters are located in the Earthly Paradise found at the top of the mountain of Purgatory. It is also said that the river flowed through the cave of Hypnos, god of sleep, where its murmuring would induce drowsiness.
Overview[]
Lethe, the river of forgetfulness, was one of the five rivers of the underworld, the other four being Styx (the river of hate), Acheron (the river of sorrow), Cocytus (the river of lamentation) and Phlegethon (the river of fire).
Another river that is to exist is the river Mnemosyne; those who drank from the Mnemosyne would remember everything and attain omniscience. Initiates were taught that they would receive a choice of rivers to drink from after death, and to drink from Mnemosyne instead of Lethe.
As such they taught their members not to drink from Lethe after they died. They believed that it was important to remember the mistakes of one's past lives so that, when reborn, one would be wiser in the next life.