Theophane was the daughter of king Bisaltes, who reigned in Thrace. She was known for her beauty and had many suitors, but Poseidon carried her off to the island of Crumissa (or Crinissa) where he metamorphosed her into a ewe and coupled with her himself as a ram. (This was a ruse to foil the suitors who had tracked her down on the island.)

Her name means 'divine showing', from theos, 'god' and phaino, 'to show'. This could mean either 'she who appears as a goddess' or 'she who makes a god appear'. The former would refer to her beauty; the latter to Poseidon.