Eurydice was a nymph in Greek mythology, one of the daughters of the god Apollo. She was married to Orpheus, a legendary musician and poet.
After their marriage, Eurydice was pursued by Aristaeus; in her effort to evade him, she stepped on a snake, she was bitten and died. Orpheus, devastated, started playing such a mournful melody on his lyre that the nymphs and gods wept in pain; they advised him to search for Eurydice in the Underworld and bring her back.
Passing through the Gates of the Underworld, his singing and his melody touched even the hearts of the God of the Underworld, Hades, and his wife, Persephone. Even the Furies could not withhold their tears. So, he was allowed to take Eurydice back to the surface. He was told however to walk in front of her and not look at her until both of them had reached the daylight. On their way back, though, Orpheus was wondering whether Hades had tricked him. So, when he reached the top and had just stepped into the daylight, he turned his head; as Eurydice had not yet reached the surface, she immediately disappeared back in the Underworld.
When Orpheus was killed by the Maenads, he was once again reunited with his betrothed.
See Also: Orpheus, Orpheus and Eurydice, The Underworld, Hades