Origin of foster son
Examples from the Web for foster son
And he told his foster-son all, how he was not his father, but had taken him to nourish at Merlin's request.Stories of King Arthur and His Knights|U. Waldo Cutler
After a week of suffering, the brave knight expired in the arms of his foster-son, February 24, 1570.
If he does not teach him his handicraft, that foster-son may return to the house of his father.Archology and the Bible|George A. Barton
Then Einar Tambaskelfer said, "Too great an earl—too great an earl, my foster-son!"Heimskringla|Snorri Sturlason
At the court of King Alf lived his foster-son Siegfried, who was much beloved by the king, although he was not of his own blood.Stories from Northern Myths|Emilie Kip Baker