Up until 1564, the French celebrated New Year’s between March 25 and April 1, but with the introduction of the new Gregorian calendar the festival was moved to January 1.
Those who resisted became the victims of pranks including invitations to non-existent New Year’s parties on April 1.
Soon the April 1 celebration of a non-occasion became an annual festival of hoaxes.
I belive that April fools day began when someone a long time ago who musted of knowed alot people by then did somethink very foolish in April and because it was so bad trick people stilled rememerd it, or someone did a silly trick and everyone stilled remered it.