Saba

According to Ossianic lore, Saba was married to Finn and the mother of Oisin. She was captured by Finn in the form of a fawn and he let her take refuse in the Sun of Allen when he realised his man-hounds couldn't hurt her. He discovered her the next morning In the form of a beautiful woman as an enchanter told her that she would revert to her original form as soon as she reached the Dun of Allen.

Finn married her and stopped joining in the hunt and the chase for some time, until he heard that the Northmen's warships were in the Bay of Dublin. He gathered his men and headed to fight them, and returned in triumph only to find Saba had gone. She was taken by the enchanter who appeared to her in disguise as Finn, making her a fawn once more.