Why April Fool’s Day?

Before 1562 April 1 was the day of the New Year observance under the Julian calendar. In 1562 Pope Gregory XIII reformed the Julian calendar into what we now call the Gregorian calendar (named after this pope). Under the Gregorian calendar January 1 is the day of the New Year observance. It took until 1578 for the new calendar to be introduced into most catholic countries.

In France between 1562 and 1578 some people were slow to adapt the calendar change. These people were called April fools. People played tricks on them to see if they would fall for the jokes. If they did they would shout out, “April fool”. The tradition took hold in the form we see it today.