Hypnos was one of a number of minor ancient deities of the Greek pantheon. He was the son of Nyx - emblematic of Night - and Erebus - also known as the pure darkness of Hades. Together with his twin brother Thanatos - the god of Death - he resided in a dark cave surrounded by poppies and other sleep-inducing herbs by the banks of the river Lethe.
Hypnos was a gentle and benevolent god who sometimes took the form of a singing bird that carried a drinking horn, from which he would pour his sleep-inducing opium. He would also deliver mortals from pain and mental suffering and, with the help of his sons and brother Oniros - Dream - would enrich their sleep with dreams. He was the most beloved of the Muses, and with his wife Pasithea had three sons, Morpheus, Phobetor, and Phantasus who would, respectively, appear in human form, as birds and animals, and as all the animate objects of our dreams.