Okay kiddo, so you know how some people wear hats to show what job they do or what school they go to? Cap and bells are kind of like that, but for special people called jesters.
Jesters were silly people who made the king or queen and all the fancy people laugh. They wore cap and bells to show that they were jesters and not regular people. The cap is like a hat that covers the head, and the bells are like little jingly things that hang from the hat.
When jesters wore their cap and bells, they would also wear colorful clothes and do silly tricks to entertain everyone. It was like they were saying "hey everyone, don't take me too seriously, I'm just here to make you laugh!"
Even though cap and bells were mostly worn a long time ago, sometimes people still wear them for fun or for costumes. So now you know all about cap and bells, and the silly people who wore them a long time ago.