The Humpbacked Horse

Someone got into the habit of trampling the crops of the peasant at night. He decided to send his sons to see who does this. And only Ivan managed to catch the guilty. He did not close his eyes all night; in the morning he saw a golden-maned horse in the field of his father. He grabbed the horse, jumped on his back and held tight. The horse could not stand it, asked to let her go. And in return she will send him her three sons. A peasant can sell two, but let him leave the last one, similar to a donkey.