April Fools History Tied to Gregorian Calendar

April FoolsApril 1 or April Fools’ Day is when people around the world play practical jokes on each other. This day has no definite origin but is commonly associated with France changing from the Julian calendar to the Gregorian in 1582. News of the switch traveled slowly so some people continued to celebrate the first of the year based on the Julian calendar, which placed it the last week in March through April 1 instead of the first day of January. April Fools’ history is tied to the Gregorian calendar because those who were not aware of the new date for the New Year ended up being the butt of jokes.

The Julian calendar was put in place in 46 B. C. by Julius Caesar. It was off by 11 minutes so, over time, the miscalculation increased. Easter, which had been observed on March 21, was getting farther away each year from the spring equinox. The idea of a reformed calendar had been debated by popes and other hierarchy of the Catholic Church for hundreds of years. Leading astronomers were consulted and ideas ranged from omitting one leap day every 134 years in order to correct the solar cycle, omitting one day every 304 years to correct the lunar cycle, omitting seven days in one year for the solar cycle and three days in one year to correct the lunar cycle.

The papal commission asked the astronomer Copernicus for his opinion in 1514. He felt there was not enough known about the motions of the sun and moon to reform the calendar. He continued with his observations for 10 more years and, later, wrote his De Revolitionibus Orbium Celestium (1543). This work was used compute tables that would be the basis for the proposed reform.

The Italian scientist, Aloisius Lilius, developed the new the new system. He realized that under the Julian calendar, an extra day was added every four years in February. This eventually made the calendar too long so he came up with a different plan. He added leap days in years only divisible by four. If that same year was also divisible by 100, no extra day was added. However, if the year was divisible by 400, that year would have a leap day.

The Council of Trent had called for reform in 1563. Pope Gregory unveiled the new calendar in 1582. Originally devised just for the Catholic Church, Spain, Portugal and Italy began using the system for civil matters as well as religious. Protestants rejected it because it came from the Catholic Church. In 1700, Protestant Germany switched to using the Gregorian calendar and England adapted it in 1752. When England made the switch, Parliament deleted 11 days so when citizens went to bed on Sept. 2, the next day was Sept. 14, 1752. This prompted Benjamin Franklin to marvel at how pleasant is was for an old man to go to bed on Sept. 2nd but not have to get up until the 14th. The artist, William Hogarth, portrayed the confusion in his painting Humours of an Election (c. 1755).

April Fools
Norman Rockwell’s 1945 April Fools’ Saturday Evening Post Cover

One popular practical joke during the Middle Ages was putting a paper fish on the backs of others and referring to them as “poisson d’avril” or April fish. This came to symbolize an easily caught, young fish as well as a gullible person.

The American painter, Norman Rockwell, painted three April Fools’ covers for the Saturday Evening Post for 1943, 1945 and 1948. Readers were encouraged to find the errors such as skis worn by a man on a fishing trip. Whatever the pranks and practical jokes are for the day, Aprils Fools’ history is often tied to the confusion surrounding the creation and implementing of the Gregorian calendar.

By Cynthia Collins

Top image: Humours of an Election by William Hogarth (c. 1755)

April Fools Tradition

Gregorian calendar history

Norman Rockwell’s April Fools’ Covers

Aloisius Lilius biography

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