April Fools' Day

Sources

• Library of Congress, American Folklife Center, April Fools: The Roots of an International Tradition (Stephen Winick) — https://blogs.loc.gov/folklife/2016/03/april-fools/ → "The short answer is that nobody knows for sure"; the 1561 Eduard De Dene poem as the first certain reference and the servant's fool's errands; John Aubrey's 1686 "Fooles Holy Day" and the line that it is kept in Germany everywhere; the 1582 Gregorian calendar account as a migratory legend told in incompatible variants, and Arthur Tilley's 1904 evidence that French books were already beginning the year on January 1 by 1507; the Chaucer line, the scribal-error reading giving May 2, and that it does not qualify as hard evidence; Hilaria rejected for want of hard evidence; the 1760 Poor Robin's Almanac verse; and the Constantine and Kugel origin as a 1983 prank by Boston University professor Joseph Boskin on Associated Press reporter Fred Bayles, later retracted by the wire.
• NPR, April Fools' Day might be the world's longest-running joke. No one knows how it began — https://www.npr.org/2022/04/01/1089947257/april-fools-day-history → that nobody seems to know the day's true origins; the 1561 poem as a clear-cut reference; the Poor Robin's Almanac verse.
• Princeton University, Cotsen Children's Library blog, A Traditional April Fools Joke: Wanna Wash the Lions at the Tower of London? — https://cotsen.blogs.princeton.edu/2024/04/a-traditional-april-fools-joke-wanna-wash-the-lions-at-the-tower-of-london → Dawk's News-Letter of April 2, 1698 and the Tower Ditch lion-washing line as the first description of an April Fool's errand; the Tower Ditch as the Tower of London's moat; Aubrey as the first Englishman to mention the observance.
• Library of Congress research guide, April Fools' Day: Topics in Chronicling America — https://guides.loc.gov/chronicling-america-april-fools/selected-articles → the twelve selected digitized newspaper articles from 1871 to 1922; the San Francisco Call of April 1, 1900, Concerning the Origin of the Name and Custom of All Fools' Day, and its concession that the reason was already unclear in 1900; the suggested search terms.
• CBC News — https://amp.cbc.ca/lite/story/1.2592631 → the April 1, 1957 BBC Panorama report on a family in Ticino, Switzerland harvesting spaghetti, which the BBC considers one of the first television April Fools' hoaxes, and viewers asking where to buy a spaghetti bush; the 1998 firing of two rock radio hosts after they told listeners the mayor of Boston had died in a car crash.
• NPR — https://www.npr.org/transcripts/125444246 → the spaghetti-harvest narration, "The last two weeks of March are an anxious time for the spaghetti farmer."
• Radio New Zealand, When spaghetti grew on trees — https://www.rnz.co.nz/news/top/300455/when-spaghetti-grew-on-trees → the April 1, 1957 date, the Swiss family, and viewers calling in to ask whether it was true and how to grow such a tree.
• The Philadelphia Inquirer — https://inquirer.com/history/taco-bell-april-fools-day-prank-20250331.html → the 1996 Taco Liberty Bell full-page ad claiming Taco Bell had bought the Liberty Bell; the flood of angry calls to newspapers and the National Park Service; Park Service spokesperson Ann Marie DiSerafino's "I believe I started hyperventilating"; the $50,000 donation.
• NASA, Astronomy Picture of the Day, April 1, 2002, Hubble Resolves Expiration Date For Green Cheese Moon — https://science.nasa.gov/image-article/apod-2002-april-1-hubble-resolves-expiration-date-for-green-cheese-moon/ → NASA's April 1 spoof tradition, signed off as such, and the green cheese moon entry.

No source conflict needed resolving on this page. The one disagreement found was over how many newspapers carried the 1996 Taco Bell advertisement — the Philadelphia Inquirer says six, NPR says two — so the page gives no number.

Not claimed, for want of a source: the 1962 Swedish television nylon-stocking color hoax; Burger King's 1998 Left-Handed Whopper, for which no contemporaneous reporting could be found; Italy's pesce d'aprile custom; Iran's Sizdah Bedar as an ancestor of April Fools' Day, since the Associated Press report on that festival mentions neither pranking nor any April Fools connection; Holi as the origin, which the Library of Congress lists among guesses with no firm evidence; the narrator, audience size or number of calls for the 1957 spaghetti film, none of which appear in the sources reached; the volume of calls the Taco Liberty Bell drew; and any figure for the economic cost of April Fools' hoaxes or the rate of corporate participation, for which nothing reputable exists.

Rejected as sources: nationaltoday, nationaldaycalendar, checkiday, timeanddate, history.com, the Museum of Hoaxes, and content-farm or AI-generated listicles. Encyclopaedia Britannica's April Fools' Day article was reachable but its body text did not retrieve, and the BBC's own archive pages for the 1957 film could not be reached from this run, so the spaghetti harvest is cited to CBC, NPR and Radio New Zealand rather than to the broadcaster itself.