April Fool's Day is celebrated on 1 April every year. 1 April is not a national holiday, but is widely recognized and celebrated in various countries as a day when people play jokes.Precursors of April Fools' Day include the Roman festival of Hilaria, held 25 March, and the Medieval Feast of Fools, held 28 December, still a day on which pranks are played in Spanish-speaking countries.In the Middle Ages, up until the late 18th century, New Year's Day was celebrated on 25 March in most European towns. In some areas of France, New Year's was a week-long holiday ending on 1 April. Many writers suggest that April Fools originated because those who celebrated on 1 January made fun of those who celebrated on other dates.
This, because of the change of the calendary, which became Gregorian.