There are several different accounts on how April Fools Day began. The generally accepted reason involves the Gregorian calendar reform of the mid sixteenth century.In 1582 France became the first country to switch from the Julian to the Gregorian calendar established by the Council of Trent (1563). The 'old' calendar had April 1 as the start of the New Year.

Some people didn't want the date to changed or they had trouble remembering the new date. Those who refused to acknowledge the new date or simply forgot received foolish gifts and invitations to nonexistent parties. The victims of this prank were given the epithet Poisson d'Avril, or April Fish. This gave birth to April Fool's Day.

The tradition eventually spread to England and Scotland in the eighteenth century. In Scotland April Fool's Day is actually celebrated for two days. Mexico's counterpart of April Fool's Day is observed on December 28. It was later introduced to the American colonies of both the English and French. April Fool's Day thus developed into an international fun fest, with different nations evolving their own kinds of fun and prank.