Everyone knows that April Fools’ Day is a celebration of jokes, tricks, pranks and “pulling one over” on others .

For the Top 100 April Fool’s Day hoaxes of all time - click here.

But, where did it all begin? Its origins are actually uncertain. Some see it as a celebration related to the turn of the seasons (people’s general joy and lightheartedness at the coming of spring), while others believe it stems from the adoption of a new calendar. Ancient cultures, including those as varied as the Romans and the Hindus, celebrated New Year’s Day on or around April 1. It closely follows the vernal equinox (March 20th or March 21st.) In medieval times, much of Europe celebrated March 25, the Feast of Annunciation, as the beginning of the new year.

In 1582, Pope Gregory XIII ordered a new calendar (the Gregorian Calendar) to replace the old Julian Calendar. The new calendar called for New Year’s Day to be celebrated Jan. 1. That year, France adopted the reformed calendar and shifted New Year’s day to Jan. 1.

According to a popular explanation, many people either refused to accept the new date, or did not learn about it, and continued to celebrate New Year’s Day on April 1. Other people began to make fun of these traditionalists, sending them on “fool’s errands” or trying to trick them into believing something false. Eventually, the practice spread throughout Europe.

There are at least two difficulties with this explanation. The first is that it doesn’t fully account for the spread of April Fools’ Day to other European countries. The Gregorian calendar was not adopted by England until 1752, for example, but April Fools’ Day was already well established there by that point. The second is that we have no direct historical evidence for this explanation, only conjecture, and that conjecture appears to have been made more recently. For more info, go to http://www.infoplease.com/spot/aprilfools1.html.

If the joke is on you this April Fools’ Day, take the advice of Max Eastman, “It is the ability to take a joke, not make one, that proves you have a sense of humor.”