Hypnos comes from the name of his Latin counterpart, Somnus. (in- "not" + somnus "sleep"), as well as a few less-common words such as "somnolent", meaning sleepy or tending to cause sleep and hypersomnia meaning excessive sleep, which can be caused by many conditions (known as secondary hypersomnia) or a rare sleep disorder causing excessive sleep with unknown cause, called Idiopathic Hypersomnia. 3D model of "Bronze head of Hypnos" via laser scan of a cast of British Museum's bronze. Hypnos In Greek mythology, Hypnos (; , "sleep") is the personification of sleep; the Roman equivalent is known as Somnus. In the
Greek mythology was their sexual companion, to every important god except Ares and to many legendary figures. Previously existing myths, such as those of Achilles and Patroclus, also then were cast in a pederastic light. Alexandrian poets at first, then more generally literary mythographers in the early Roman Empire, often re-adapted stories of Greek mythological characters in this fashion. The achievement of epic poetry was to create story-cycles and, as a result, to develop a new sense of mythological chronology. Thus Greek mythology unfolds as a phase in the development of the world and of humans. While self-contradictions in these stories make