Jesters were entertainers in medieval times who were employed to entertain nobility or entertain commoners at fairs and markets. They employed a wide variety of skills including music, storytelling, acrobatics, juggling and song usually in a comic style. Many jesters made jokes about people or events known to their audience.
1) Use of the word "jester" in the modern sense did not begin until the mid-16th century.
2) Jesters served both to amuse and criticize their master/mistress and their guests.
3) They enjoyed a privileged status in a noble household.
4) Jesters could give bad news that no one else dare deliver.