A jester, also known as joker, court jester, or fool, was a member of the household of a nobleman or a monarch employed to entertain guests during royal court. Jesters were also traveling performers who entertained common folk at fairs and town markets, and the discipline continues into the modern day, where jesters perform at historical-themed events. During the post-classical and Renaissance eras, jesters are often thought to have worn brightly coloured clothes and eccentric hats in a motley pattern. Their modern counterparts usually mimic this costume.
https://en.wikipedia.org/wiki/Jester