What's the origin of April Fool's Day?
Dear Straight Dope:
What's the deal with April Fool's Day? I hear it has some sort of French ancestry, something to do with fish??? What gives Straight Dope posse?
You couldn't be more wrong.
April Fool's Day was originally graduation day in the Middle Ages, when court jesters received their caps and bells and were sent to castles all over Europe.
(OK, so it's May. Punctuality is not our strong suit around here.)
The origin of April Fool's Day is uncertain, but there are lots of theories. The most commonly heard one has to do with the switch from the Julian to the Gregorian calendar. Here's how Charles Panati tells it in Extraordinary Origins of Everyday Things (1987):
Throughout France in the early sixteenth century, New Year's Day was observed on March 25, the advent of spring. The celebrations, which included exchanging gifts, ran for a week, terminating with dinners and parties on April 1.
In 1564, however, in beginning the adoption of the reformed, more accurate Gregorian calendar, King Charles proclaimed that New Year's Day be moved back to January 1. Many Frenchmen who resisted the change, and others who merely forgot about it, continued partying and exchanging gifts during the week ending April 1. Jokers ridiculed these conservatives' steadfast attachment to the old New Year's date by sending foolish gifts known as poisson d'avril, or "April fish" (because at that time of year the sun was leaving the zodiacal sign of Pisces, the fish)....
Years later, when the country was comfortable with the new New Year's date, Frenchmen, fondly attached to whimsical April Fooling, made the practice a tradition in its own right.
There's a small problem with this story and a big one. The small problem is that the Gregorian calendar wasn't introduced until 1582. (For what it's worth, the Encyclopedia Britannica tells a substantially similar story using the correct date.) The big problem is that the story seems to be mainly conjecture. If there's any primary evidence to support it we haven't seen it. Not all countries adopted the Gregorian calendar at the same time--England, Scotland, and Germany didn't do it until the 18th century. Yet the April Fool's tradition is said to have been well established throughout Europe by then.
There were celebrations of foolishness before 1582. Those close to April 1 include (I'm relying on the EB here) the ancient Roman festival of Hilaria, celebrated March 25, and the Holi celebration in India, which ends March 31. Going farther afield we have the Roman winter solstice celebration of Saturnalia, which by medieval times had evolved into the Festus Fatuorum (the Feast of Fools). This was celebrated mostly in France and was suppressed, interestingly, in the 16th century, around the time Gregorian-calendar theory has April Fool's Day starting.
Wish we could be more definite. But we won't fool you by telling you we have the facts when we don't.