Hypnos, Latin Somnus, Greco-Roman god of sleep. Hypnos was the son of Nyx (Night) and the twin brother of Thanatos (Death). In Greek myth he is variously described as living in the underworld or on the island of Lemnos ( according to Homer) or (according to Book XI of Ovid’s Metamorphoses) in a dark, musty cave in the land of the Cimmerians, through which flowed the waters of Lethe, the river of forgetfulness and oblivion. Hypnos lay on his soft couch, surrounded by his many sons, who were the bringers of dreams. Chief among them were Morpheus, who brought dreams of men; Icelus, who brought dreams of animals; and Phantasus, who brought dreams of inanimate things.