She has a son in a pigsty. Wise William is sent to seek her; he sends his wife, and when she finds her, she persuades her to change her son for her daughter, saying that they will both raise the other's child fittingly.
A mother has a child living in an unhygienic environment. A wise man is sent to find her; he dispatches his wife, and when she finds the woman, she convinces her to exchange their children, suggesting they will both raise the other's offspring suitably.