There was a king in a land not far from Greece who had two daughters, and the younger was fairer than the elder daughter.
This old king made a match between the king of Greece and his own elder daughter; but he kept the younger one hidden away till after the marriage. Then the younger daughter came forth to view; and when the king of Greece saw her, he wouldn't look at his own wife. Nothing would do him but to get the younger sister and leave the elder at home with her father.
The king wouldn't listen to this, wouldn't agree to the change, so the king of Greece left his wife where she was, went home alone in a terrible rage and collected all his forces to march against the kingdom of his father-in-law.
He soon conquered the king and his army and, so far as he was able, he vexed and tormented him. To do this the more completely, he took from him a rod of Druidic spells, enchantment, and ring of youth which he had, and, striking the elder sister with the rod, he said: "You will be a serpent of the sea and live outside there in the bay by the castle."
Then turning to the younger sister, whose name was Gil an Og, he struck her, and said: "You'll be a cat while inside this castle, and have your own form only when you are outside the walls."
After he had done this, the king of Greece went home to his own country, taking with him the rod of enchantment and the ring of youth. The king died in misery and grief, leaving his two daughters spellbound.
Now there was a Druid in that kingdom, and the younger sister went to consult him, and asked: "Shall I ever be released from the enchantment that's on me now?"
"You will not, unless you find the man to release you; and there is no man in the world to do that but a champion who is now with Fin MacCumhail in Erin."
"Well, how can I find that man?" asked she.
"I will tell you," said the Druid. "Do you make a shirt out of your own hair, take it with you, and never stop till you land in Erin and find Fin and his men; the man that the shirt will fit is the man who will release you.