“April Fool’s!” You’ll hear Americans yell after their co-worker discovers his stapler in Jell-O. In Brazil April 1st is called Dia da Mentira or “Day of the lie,” while in France children tape a picture of a fish on their friends’ backs and yell “Poisson d’Avril!” or “April fish!” The fish symbolizes a naive and easily caught (gullible) person. It’s all in good fun and part of a time honored tradition dating back to ancient times.

Two Ideas of Origin

The exact origin of April Fool’s Day is unknown. The festival could date back to the ancient Romans who celebrated Hilaria in honor of the goddess Cybele. It was a way to acknowledge the unpredictable weather patterns as winter shifted to spring, and how many people went a little stir crazy during the transition. Festival revelers often donned disguises and played tricks.

For many cultures, April 1 was the first day of the new year. The ancient Hindus celebrated New Year’s Day on or around April 1, using the vernal equinox not only as a seasonal marker but also a calendar shift. Europeans in medieval times marked the Feast of Annunciation, March 25, as the new year and often celebrated for a few days.

In 1582, Pope Gregory XIII changed everything. He ordered the Gregorian Calendar, which marks the new year on January 1, to replace the Julian Calendar. Though France adopted the new calendar right away, some people either refused to follow the new calendar or did not learn the news of the change, and continued to celebrate the new year on April 1. Many believe that this was the start of April Fool’s day. Those following the Gregorian Calendar would trick the traditionalists into running “fool’s errands” or find other tricks to play on them.

The problem with this origin story are the conflicting dates of the acceptance by many European countries of the Gregorian Calendar and the oldest recorded celebrations of their April Fool’s Day. For example, England didn’t adopt the calendar until 1752, but the country was already celebrating April Fool’s Day by then. By the 1700s Scotland had begun a 2-day tradition of playing “hunting the gowk,” a gowk means cuckoo bird, the symbol for fool, and Tailie Day where pranksters pinned “kick me” signs onto people’s backs.

A Third Alternative

In 1983 a history professor at Boston University, Joseph Boskin, offered another explanation for April Fool’s Day, tracing it to the reign of Constantine. Allegedly, a group of court jesters told the emperor they could do a better job running the empire. Constantine thought the idea was interesting and allowed a jester named Kugel to be king for a day. King Kugel passed a law calling for trickery and absurdity on that day. The court enjoyed it so much, it became an annual custom.

The Associated Press printed an article featuring Boskin’s explanation. It came out that initially during the interview, Boskin told the reporter he truly didn’t know the origin of April Fool’s Day, but the reporter kept pressing him so he decided to invent one. As the AP is known for their fact-checking, Boskin was sure the reporter would catch the joke, especially since he chose the name Kugel after a popular Jewish dish. Instead it became one the best April Fool’s joke of the century!

Best April Fool’s Pranks

The best pranks are those that are good-natured, and do not cause harm to participants. It’s especially fun to see ridiculous April Fool’s claims convince the most gullible among us. Here are some of the funniest public gotcha pranks in recent times:

1957- The BBC reported Swiss farmers were having a record spaghetti crop. Yes, spaghetti crop. They showed footage of farmers pulling strands of noodles from trees.

1985- Sports Illustrated ran an article about a rookie pitcher, Sidd Finch, who could throw fastballs over 168 mph. Fact-checking, the fastest baseball pitch recorded ever was in 2010 at 105.1 mph.

1996- The fast food chain, Taco Bell, announced it will be purchasing Philadelphia’s historical Liberty Bell and renaming it the “Taco Liberty Bell.” Some people were quite upset about this proposal.

1998- The fast food burger chain, Burger King, advertised a bogus sandwich called the “Left-handed Whopper.” An embarrassing number of customers ordered the sandwich.

April Fool’s Day is meant to celebrate an “all in good fun” attitude. Hopefully the custom of harmless pranks will survive the internet age, when every day we actually do have to question the credibility of companies and news sources. April 2 apology letters are becoming the norm, thanks to a combination of increased sensitivity, gullibility, and blatant line-crossing. It’s hard to enjoy April Fool’s Day when wacky is an everyday occurrence and skepticism has almost become a survival instinct.

However, it is fun and probably productive to take a break from taking ourselves too seriously. With that in mind, take April Fool’s Day in stride: stay alert, be wary of anyone being too nice to you, and try to stay ahead of the gullible pack. You’re sure to have a laugh with the sugar-salt swap or changing a friend’s cell phone ringtone to something very loud and embarrassing.