In the Greek mythology, Hypnos is the son of Nyx ("The Night") and Erebus ("The Darkness"). His brother is Thanatos ("Death"). Both siblings live in the underworld (Hades) or in Erebus, another valley of the Greek underworld. According to rumors, Hypnos lived in a big cave, which the river Lethe ("Forgetfulness") comes from and where night and day meet. His bed is made of ebony, on the entrance of the cave grow a number of poppies and other hypnotic plants. No light and no sound would ever enter his grotto. According to Homer, he lives on the island Lemnos, which later on has been claimed to be his very own dream-island. He is said to be a calm and gentle god, as he helps humans in need and, due to their sleep, owns half of their lives.