April Fools' Day might be the world's longest-running joke. No one knows how it began

Some historians have linked April Fools’ Day to the ancient Roman festival of “Hilaria,” where at the end of March, people would come together to commemorate the resurrection of the god Attis. It was a celebration of renewal in which revelers would dress up in disguises and imitate others.

It’s also possible that the medieval celebration of the Feast of Fools, where a mock bishop or pope was elected and church customs were parodied, could have inspired the day.

Some gullible “fish” might also explain the tradition

Other historians believe April Fools’ Day has its origins in the 16th century, when France switched from the Julian calendar to the Gregorian calendar.

The Julian calendar began in March with the spring equinox and was celebrated until April 1. By switching to the Gregorian calendar, the new year would now begin on Jan. 1.

News traveled slowly back then, and not everyone knew about or was willing to change when to celebrate the new year. Those who continued to celebrate in the spring were often ridiculed and made the butt of jokes.

Some pranks included having a paper fish placed on a person’s back as they were called “poisson d’avril,” or “April fish.”

One of the first known references to this term, “poisson d’avril,” is found in a 1508 poem written by Eloy d’Amerval. The phrase itself doesn’t necessarily mean there was a holiday on April 1, but the idea of the “April fish” is that fish were more plentiful in the spring and thus easier to catch. In other words, an “April fish” was more gullible than fish caught in other seasons.

In 1561, an early, clear-cut reference to April Fools’ Day appears in a Flemish poem written by Eduard de Dene. In the poem, a nobleman sends his servant out on a series of wild errands. The servant eventually realizes that these are “fool’s errands” because the date is April 1.

Scholars say one of the first mentions of an April Fools’ Day in English appears in John Aubrey’s 1686 book Remaines of Gentilisme and Judaisme, which reads, in part: “We observe it on the first of April. And so, it is kept in Germany everywhere.”

Even in 1760 there was speculation as to the origins of the holiday, with a line in Poor Robin’s Almanac reading:

“The First of April some do say. Is set apart for all Fool’s Day. But why the people call it so. Nor I nor they themselves do know”

The media has been in on the joke for years

The tradition has evolved over the years with modern forms of media upping the ante on pranks and tricks. Newspapers, radio, TV stations and websites have all participated in the tradition, making April 1 a day where everyone truly needs to be on their guard.

On April 1, 1905, for example, a German newspaper wrote that thieves had dug a tunnel underneath the U.S. Treasury and stolen $268 million in silver and gold.

One of the more famous pranks occurred in 1957, when the BBC aired a segment showing Swiss harvesters picking spaghetti off trees and bushes, claiming the region had had “an exceptionally heavy spaghetti crop” that year.

NPR has gotten in on the fun too. In 1992, the show Talk of the Nation ran a hoax story in which Richard Nixon — played by Rich Little — announced he was running for president again with the slogan “I didn’t do anything wrong, and I won’t do it again.”

On April 1, 2014, NPR published an article titled “Why Doesn’t America Read Anymore?” The post sparked heated debate on social media — particularly among those who neglected to actually click on the link. Those who did were greeted with a challenge:

“Congratulations, genuine readers, and happy April Fools’ Day! We sometimes get the sense that some people are commenting on NPR stories that they haven’t actually read. If you are reading this, please like this post and do not comment on it. Then let’s see what people have to say about this ‘story.'”

Although we may never know its true origins, April 1 has come to represent a day of joy and comedy as we move out of the darkness of winter and into the spring.

And no matter how you choose to celebrate the day, it’s best to be wary of what you read and what you hear on April Fools’ Day.

Except for this story, of course.