The Feast of Fools April Fools Day. It has its roots in a long forgotten Christian religious festival. No fooling! To quote Harvey Cox: "During the medieval era there flourished in parts of Europe a holiday known as the Feast of Fools. On that colorful occasion ... even ordinarily pious priests and serious townsfolk donned bawdy masks, sang outrageous ditties, and generally kept the whole world awake with revelry and satire.