April Fool's Day or All Fool's Day occurs annually on April 1. The day is generally observed by playing a practical joke on a "victim" who soon becomes known as an April Fool. This custom is thought to have started in France during the 16th century but the British are credited with bringing it to the United States.

The origin of April Fool's Day remains clouded in obscurity. Basically no one knows exactly where, when, or why the celebration began. What we do know is that references to 'All Fool's Day' (what April Fool's Day was first called) began to appear in Europe during the late Middle Ages.

All Fool's Day was a folk celebration and elite participation in it appears to have been minimal (which is why it's so difficult to trace the exact origin of the day, because the people celebrating it back then weren't the kind of people who kept records of what they did). But what is clear is that the tradition of a day devoted to foolery had ancient roots.