In Irish mythology, Sadhbh or Sive (/saɪv/ SYVE) was the mother of Oisín by Fionn mac Cumhail.
The legend goes that Sadhbh was enchanted to take the form of a doe for refusing the love of Bob Doireach (or Fear Doirche), the dark druid of the Men of Dea (here meaning the Tuatha Dé Danann).
A false image of Fionn and of Bran and Sceolan appeared outside the dún and Sadhbh ran out to her husband, unaware of the danger.
As soon as she reached the false image it changed to reveal the Fear Doirche, who took out a wand made of hazel and struck her, thus she became a deer once more.
At the end of these seven long years, a wild boy was found in the forest while the Fianna hunted.