The full tale
Once upon a time there was a prince who wanted to marry a real princess. So he traveled all over the world to find her, but he couldn't find one anywhere. There were plenty of princesses, but he could never be sure whether any of them was a real one.
Something always seemed wrong to him—one seemed to be putting on an act, another was too proud, and yet another was too childish. The prince wanted to be certain that his future bride would be a real princess.
One evening, a storm raged—lightning split the sky, thunder rumbled, and the rain came down in buckets. Suddenly, someone knocked at the castle gate.
The old king himself went to open it. Outside the gate stood a girl—soaked to the skin, water dripping from her hair and her clothes, and her shoes squelching. And yet she said that she was a real princess.
We'll soon see about that, thought the queen, the prince's mother. Without a word, she went to the guest room, took all the bedding off the bed, placed one tiny pea at the very bottom, and then covered it with twenty mattresses and twenty featherbeds filled with down.
The princess was put to bed there for the night.
In the morning, the queen asked her how she had slept.
"Oh, terribly!" the princess answered. "I hardly closed my eyes all night. Something hard was lying under the mattresses. I'm bruised all over! It was awful!"
Then everyone understood that she was a real princess—because through twenty mattresses and twenty featherbeds she had felt a tiny little pea.
Only a real princess could be so sensitive.
The prince was overjoyed, for at last he had found the one he had been looking for. Soon they were married.
And the pea went to the royal museum, where it could still be seen for many years afterward—unless somebody took it.