I’m very familiar with this fairy tale! Thinking about it though, it is a very strange one. It centres around a prince who wants to marry a princess. He really wants to make sure she’s a real princess. He travels around to find one but can’t find a real one.
One night a princess knocks on the castle door. She’s soaked from a storm and doesn’t look like a princess. The queen knows she’s a princess (somehow) so she puts a pea under many, many mattresses and quilts. She tells the princess to sleep on top of them.
The next morning the princess says that she didn’t sleep very well and was bruised by something in the bed. Somehow, this makes the princess a real princess, because apparently only real princesses are that sensitive. The princess marries the prince and the pea is kept inside a museum! (Ha!)