Washington, Apr 1 (ANI): Although April Fool's Day is not an official holiday but plenty of pranksters and joke-lovers dupe friends and loved ones throughout the day. However, no one knows exactly when or how this tradition began.

It is believed that the day coincided with the coming of spring since the time of the Ancient Romans and Celts, who celebrated a festival of mischief-making. The first mentions of an All Fool's Day (as it was formerly called) came in Europe in the Middle Ages, reports Live science.

According to some people, the fun-loving day can be traced back to Roman mythology, particularly the story of Ceres, Goddess of the harvest, and her daughter, Proserpina.

However, the most widespread theory of the origin of the day is the switch from the old Julian to the Gregorian calendar in the late 16th century. Under the Julian calendar, the New Year was celebrated during the week between March 25 and April 1, but under the Gregorian calendar, it was moved to Jan. 1.

Those who were not notified of the change, or stubbornly kept to the old tradition, were often mocked and had jokes played on them on or around the old New Year.

In Scotland, the butts of April Fool's jokes were known as April "Gowks," another name for a cuckoo bird. (ANI)