Everyone believes that the origins of April Fool’s Day came from the mistake involving the Gregorian and Julian Calendar, in which those who had not changed  to the Gregorian Calendar yet were called ‘fools’ and had paper fishes posted onto their backs, as a joke. This idea evolved from the french, whose many rural farmers either refused to adapt to the new Gregorian Calendar or were not informed of the calendar, thus many of them were mocked. For example, the fish posted on the back of a ‘fool’ was referred to as ‘Poission d’Avril’, the fish of April.