Etain: Irish goddess and one of the Tuatha De Danann
Etain is an Irish goddess and one of the Tuatha De Danann. She is famous for being reincarnated several times and being an accomplished horse rider (and she is beautiful and blond).
She was the second wife of the god Midir. But Midir's first wife was jealous of Etain and by a Druid's spell Etain was transformed into a pool of water, a worm and finally a fly.
But as luck would have it, the Uster warrior Etar's wife swallowed the fly and became pregnant with Etain. Thus she was born as a mortal, oblivious to her previous existance as a goddess.
As a human, Etain was whoed by two prominent brothers, one who was the High King Eochaidh. But one day she suddenly remembered that she was already married to Midir and went to live with Midir. This did not last long either and she returned to Tara to live a mortal life as the Eochaidh's queen.