A Lithuanian fairy tale, this version was published in the Violet Fairy Book by Andrew Lang, in 1901.
Once on a time there were three princes, who had a step-sister. One day they all set out hunting together. When they had gone some way through a thick wood they came on a great grey wolf with three cubs. Just as they were going to shoot, the wolf spoke and said, ‘Do not shoot me, and I will give each of you one of my young ones. It will be a faithful friend to you.’