Orpheus, in Greek mythology, poet and musician, the son of the muse Calliope (see Muses) and Apollo, god of music, or Oeagrus, king of Thrace. He was given the lyre by Apollo and became such an excellent musician that he had no rival among mortals. When Orpheus played and sang, he moved everything animate and inanimate. His music enchanted the trees and rocks and tamed wild beasts, and even the rivers turned in their course to follow him.

Orpheus is best known for his ill-fated marriage to the lovely nymph Eurydice. Soon after the wedding the bride was stung by a viper and died. Overwhelmed with grief, Orpheus determined to go to the underworld and try to bring her back, something no mortal had ever done. Hades, the ruler of the underworld, was so moved by his playing that he gave Eurydice back to Orpheus on the one condition that he not look back until they reached the upperworld. Orpheus could not control his eagerness, however, and as he gained the light of day he looked back a moment too soon, and Eurydice vanished. In his despair, Orpheus forsook human company and wandered in the wilds, playing for the rocks and trees and rivers. Finally a fierce band of Thracian women, who were followers of the god Dionysus, came upon the gentle musician and killed him. When they threw his severed head in the river Hebrus, it continued to call for Eurydice, and was finally carried to the shore of Lesbos, where the Muses buried it. After Orpheus's death his lyre became the constellation Lyra.

For the importance of Orpheus in Greek religious history, see Orphism.