Orpheus was a talented musician. He played the lyre and was said to be able to tame lions and tigers with his music. It was said to be so beautiful, he could charm fish out of the water, summon birds from the skies, lure wild beasts out of the forests and coax trees and rocks into dancing.
Orpheus is said to be married to Eurydice. She was walking through the long grass when she was bitten by a venomous viper and died. Orpheus found her body and played his music so sadly, that all the nymphs and gods attending wept. The gods advised Orpheus to travel to the Underworld to plead for the return of Eurydice, and he did, playing such sweet music it softened the hearts of Hades and Persephone (the only person to ever do so), who agreed under only one condition; he was to walk in front and not look back until they reached the upper world or she would stay in the Underworld forever.
In his anxiety, before she reached the upper world, he turned back to look at her and she vanished into the Underworld, this time it would be forever.