In Greek mythology, the Oneiroi were the sons of Hypnos, the god of sleep. They were personifications of dreams—black-winged daemon—and were said to live on the shores of the Ocean in the far West, in a cavern near the border of Hades. The gods sent dreams to mortals from one of two gates located there: true dreams emerged from a gate made of horn, whereas false dreams threaded their way from a gate fashioned of ivory. They are described in the Odyssey, Hesiod's Theogony, and Ovid's Metamorphoses. According to Euripides, their mother was Gaea.The most powerful of the Oneiroi was Morpheus. His brothers Phobetor (also known as Icelus) and Phantasos crafted parts of dreams, while he formed the dream in general. Morpheus shaped human figures, Phobetor animal, while Phantasos shaped inanimate objects.
Oneiroi in Pop Culture
Fates Warning, a progressive metal band, has a side long epic on their 1988 release No Exit titled The Ivory Gate of Dreams which touches on this myth.