April Fools' Day (sometimes called April Fool's Day or All Fools' Day) is celebrated every year on the first day of April. Popular since the 19th century, the day is not a national holiday in any country, but it is well known in Europe, Australia, Brazil and the United States, and it is celebrated as a day when people play practical jokes and hoaxes on each other. The jokes and their victims are known as "April fools". Hoax stories may be reported by the press and other media on this day and explained on subsequent days.
The earliest recorded association between April 1 and foolishness can be found in Chaucer's The Canterbury Tales (1392). Many writers suggest that the restoration of January 1 as New Year's Day in the 16th century was responsible for the creation of the holiday, but this theory does not explain earlier references.