Once there was a Prince who lived in a wealthy kingdom. When he had reached the proper age his mother the queen decided the time was right to find a bride. The prince however was determined not to marry just any girl, and decided that only a "real" princess would do for his future wife should. Therefore he set off to travel through all the world to find her, and although he searched in all the kingdoms and met with all the princesses it didn’t quite go right. There were many Princesses, but how was he to know whether they were real? There was something not quite right about them all. Eventually he came home again unsatisfied and unhappy, because he wanted to have a real Princess so much.
Then one night a terrible storm blew in. The rain poured down and the lightning was so bright that it lit up the palace as though it were daytime and the thunder was so loud that it set all the palace dogs to howling. In the middle of the storm there was a knocking at the palace door. The old King went to open it, and who should be there but a girl claiming to be a true Princess. She was a terrible sight with her hair all over the place and her clothes soaked through, but she was invited in to stay for the night.
The old Queen didn’t believe for a minute that she was a real Princess and so she decided to test the young girl's claim. Without saying a word to anyone she went into the guest bedroom, took all the bedding off the bedstead, and laid a single pea on the bottom; then she took twenty mattresses and piled them on top of the pea, and then she laid twenty eiderdown quilts on top of the mattresses. On this the Princess had to sleep all night. The next morning when the girl woke up, the Queen asked how she had slept.
"Oh, very poorly!" she said. "I scarcely closed my eyes all night. Heaven only knows what was in the bed, but I was lying on something hard, and now I am black and blue all over my body. It's horrible!"
They could see she was a real Princess without a single doubt because only a true Princess could have such delicate skin as to feel a pea through twenty mattresses and twenty more quilts.
So the Prince decided to marry her immediately, because he knew he had found a real Princess.