One day the brothers heard about a princess in a faraway land who was dying of an unknown disease. Rumour had it the king would let the man who saved his daughter marry her. The brothers sprung into action. The first looked in his mirror and saw the ill princess and the land she lived in. All three jumped on the second brother's horse, and they rode so fast they got to the princess' land the next morning. Then the third son took his apple to the princess, who ate it and recovered full health instantly.
The king was grateful, and indeed intended to let one of them marry the princess. But it had taken the cooperation of all three brothers to save her. Which one did the king decide should marry his daughter?