One time Finn and his men came to Slieve Crot, and they saw a woman waiting there before them, having a crimson fringed cloak, and a gold brooch in it, and a band of yellow gold on her forehead.  Finn asked her name, and where she came from.  “Etain of the Fair Hair is my name,” she said, “daughter of Aedh of the White Breast, of the hill of the Sidhe at Beinn Edair, son of Angus Og.”  “What is it brought you here, girl?” said Finn.  “To ask a man of the Fianna of Ireland to run a race with me.”  “What sort of a runner are you?” said Diarmuid.  “I am a good runner,” said the girl; “for it is the same to me if the ground is long or short under my feet.”

All of the Fianna that were there then set out to run with her, and they ran to the height over Badhamair and on to Ath Cliath, and from that on to the hill of the Sidhe at Beinn Edair.

And there was a good welcome before them, and they were brought meat and wine for drinking, and water for washing their feet.  And after a while they saw a nice fair-haired girl in front of the vats, and a cup of white silver in her hand, and she giving out drink to every one.  “It seems to me that is the girl came asking the Fianna to race against her at Slieve Crot,” said Finn.  “It is not,” said Aedh of the White Breast, “for that is the slowest woman there is among us.”  “Who was it so?” said Finn.  “It was Be-mannair, daughter of Ainceol, woman-messenger of the Tuatha de Danaan.  And it is she that changes herself into all shapes; and she will take the shape of a fly, and of a true lover, and every one leaves their secret with her.  And it was she outran you coming from the east,” he said, “and not this other girl that was drinking and making merry here in the hall.”  “What is her name?” said Finn.  “Etain of the Fair Hair,” he said; “a daughter of my own, and a darling of the Tuatha de Danaan.  And it is the way with her, she has a lover of the men of the Fianna.”  “That is well,” said Finn; “and who is that lover?” “It is Osgar, son of Oisin,” said Aedh; “and it is she herself sent her messenger for you,” he said, “in her own shape, to Slieve Crot in the south.  And the son of the High King of Ireland has offered a great bride-price to the Men of Dea for her,” he said, “three hundreds of the land nearest to Bregia and to Midhe, and to put himself and his weight of gold into a balance, and to give it all to her.  But we did not take it,” he said, “since she had no mind or wish for it herself, and so we made no dealing or agreement about her.”  “Well,” said Finn, “and what conditions will you ask of Osgar?” “Never to leave me for anything at all but my own fault,” said the girl.  “I will make that agreement with you indeed,” said Osgar.  “Give me sureties for it,” said she; “give me the sureties of Goll for the sons of Morna, and of Finn, son of Cumhal, for the Fianna of Ireland.”

So they gave those sureties, and the wedding-feast was made, and they stopped there for twenty nights.  And at the end of that time Osgar asked Finn where would he bring his wife.  “Bring her to wide Almhuin for the first seven years,” said Finn.