April Fools’ Day or April Fool’s Day (sometimes called All Fools’ Day) is an annual custom on April 1 consisting of practical jokes and hoaxes. Jokesters often expose their actions by shouting “April fools” at the recipient. Mass media can be involved in these pranks, which may be revealed as such the following day. The day is not a public holiday in any country except Odessa in Ukraine, where the first of April is an official city holiday. The custom of setting aside a day for playing harmless pranks upon one’s neighbor has been relatively common in the world historically.
A disputed association between April 1 and foolishness is in Geoffrey Chaucer’s The Canterbury Tales (1392). In the “Nun’s Priest’s Tale”, a vain cock Chauntecleer is tricked by a fox on Syn March bigan thritty dayes and two. Readers apparently understood this line to mean “32 March”, i.e. April 1. However, it is not clear that Chaucer was referencing April 1, since the text of the “Nun’s Priest’s Tale” also states that the story takes place on the day when the sun is in the signe of Taurus had y-runne Twenty degrees and one, which cannot be April 1. Modern scholars believe that there is a copying error in the extant manuscripts and that Chaucer actually wrote, Syn March was gon. If so, the passage would have originally meant 32 days after March, i.e. 2 May, the anniversary of the engagement of King Richard II of England to Anne of Bohemia, which took place in 1381.
The April joke came to Lorenzburg in the mid 17th century. The joke often played out as sending someone a letter to trick them into going on a fool’s errand.