Possible Clues:

• '___ and the Swan' (lost Michelangelo painting)
• A queen of Sparta
• Sounds like the head one with a swan
• She got involved with Aswan
• Did she make a deal with a swan?
• Castor and Pollux's mother
• Helen of Troy's mythic mother
• She got led a dance by a swan
• The French father for Aswan?
• Zeus visited her as a swan