This beautiful book illustration was painted by Kay Nielsen for the book "East of the Sun and West of the Moon Old Tales from the North". The name of this story is "The Widow's Son". He went off to find his way in the world.
He became a servant to a man who was a troll (unknowing to him). This troll kept a horse in another room as a prisoner. The boy was kind to the horse and the horse thanked him. The horse said he would repay him for his kindness. He should go to the other room and pick out the rustiest mail armour and sword and most unkept saddle for himself. He should not pick out the best and the brightest ones. So he did what he was told. Then the boy took a bath in a magic cauldron where he became sleek, handsome and strong. He put on his armour and they went off to save themselves from the troll.
After many trials and tribulations of travelling, he came to know a princess when he took a job as a gardener. The king didn't like this wretched boy with his daughter and sent him into battle thinking the boy would lose and he would be done with him.
The lad won his battle with the neighboring king because of his horse. No one knew this was the reason. But later, after the boy married the princess, he became the King of the Land. His horse turned into a Prince who had been enchanted. This enchanted Prince became King in the next town so there were no more wars after that. They all lived happily ever after.