Morpheus. Morpheus is a god associated with sleep and dreams. In Ovid's Metamorphoses he is the son of Sleep, who appears in dreams in human form. From the medieval period, the name began to stand more generally for the god of dreams, or of sleep. In Ovid's Metamorphoses, Morpheus is one of the thousand sons of Somnus. His name derives from the Greek word for form, and his function was to appear in dreams in human guise. According to Ovid no other is more skilled than he in representing the gait, the features, and the speech of men; the clothing also and the accustomed words of each he represents. Like other gods associated with sleep, Ovid makes Morpheus winged. Ovid called Morpheus and his brothers, the other sons of Somnus, the Somnia, saying that they appear in dreams mimicking many forms. Ovid gives names to two more of these sons of Sleep. One called Icelos, by the gods, but Phobetor by men, takes the form of beast or bird or the long serpent, and Phantasos, who puts on deceptive shapes of earth, rocks, water, trees, all lifeless things. The three brothers' names are found nowhere earlier than Ovid, and are perhaps Ovidian inventions. Tripp calls these three figures literary, not mythical concepts. However Griffin suggests that this division of dream forms between Morpheus and his brothers, possibly including their names, may have been of Hellenistic origin. Robert Burton, in his 1621 Anatomy of Melancholy, refers to a depiction of Morpheus, saying Philostratus paints in a white and black coat, with a horn and ivory box full of dreams, of the same colours, to signify good and bad. In Carl Michael Bellman's Fredman's Epistle No. 72, Glimmande nymf, Morpheus is invoked as the god of sleep. Friedrich Serturner derived the name of the opiate drug morphine from the name of Morpheus.