Fish, Kings, And Gotham: The Murky History Behind April Fool’s Day
Some think April Fool’s Day dates to 1564 in France, when King Charles IX moved the official start of the year from Easter to January 1. Prior to this edict, most Christian countries’ calendar began from the movable date.
Article source: https://www.huffingtonpost.co.uk/entry/april-fools-day-history_uk_69ccf090e4b010aa534923e4