What is the April Fool’s Day origin story? The April 1 tradition of pranks has been observed for several centuries across a variety of cultures. However, the official origins of April Fools’ Day is unknown.
The most popular theory is that the day was caused by the switch from the Julian calendar to the Gregorian calendar in the 16th century.
The original calendar saw the New Year beginning on March 25, with celebrations occurring on the first day of April. The switch moved the New Year to January 1, but many still thought April 1 was the proper day to celebrate, hence they were “April fools.”
Another theory says the day is related to the arrival of Spring, when nature “fools” people with irregular weather. Historians have also linked April Fools' Day to an ancient Roman festival known as Hilaria, which was celebrated by people dressing up in disguises.
Whatever its origin may be, April Fools’ Day has evolved to have its own lore and rules. Superstition says that playing pranks past noon or not responding to pranks with good humor will attract bad luck.