Étaín

Étaín, daughter of the King of Ulster, was renowned in early Irish tradition as the most beautiful woman ever to walk in Ireland — beautiful enough that when Midir, lord of the otherworldly mound of Brí Léith (now Ardagh Hill, County Longford), was struck blind in an accident, the price he demanded for his healing was her hand in marriage. His foster-son Aengus won her for him by performing a year of impossible labours — clearing forests, diverting rivers, and raising a causeway across a bog — tasks so vast they were said to reshape the land itself.

Midir's first wife Fúamnach, consumed by jealousy, turned her magic on the new bride. She transformed Étaín first into a pool of water, then into a brilliant purple fly, and finally summoned a great wind that swept the fly across Ireland for seven years, denying her any rest. When the wind at last dropped her into a golden cup of wine, the noblewoman drinking from it swallowed Étaín without ever knowing — and over a thousand years after her first birth, Étaín was reborn as a mortal child, growing up to become the wife of the High King Eochaid Airem at Tara.

Midir tracked her down at last, but rather than simply reclaiming her, he challenged Eochaid to a series of games of fidchell, each time letting the king win so that Eochaid would owe him an ever-larger favour — labours that, by tradition, produced the great Corlea Trackway across the Longford bogs. Only when Midir finally won a game did he name his true prize: a single kiss and embrace from Étaín. The moment he took it, the otherworldly lord and his reclaimed bride transformed into a pair of swans and flew out through the skylight of Tara, leaving Eochaid to tear apart the mounds of Ireland — including Brí Léith itself — in a furious, futile search for them.