There are those who will tell you that the silliness associated with April 1 began in 1582 in France with the reform of the calendar under Charles IX. The Gregorian Calendar was introduced and the week leading up to New Year’s Day was moved from March 25 through April 1 to January 1.
It all sounds very plausible except for the fact that pranks played on April 1 are documented long before 1582.
Chaucer (who has been referenced previously in other idioms at this blog) made mention of April Fool’s Day in the Nun’s Priest’s Tale from the Canterbury Tales in 1392.
When that the monthe in which the world bigan
That highte March, whan God first maked man,
Was complet, and passed were also
Syn March bigan thritty dayes and two.
In 1508, Eloy d’Amerval, a French choirmaster and composer wrote a poem entitled, “Le livre de la deablerie.” The poem includes the line, “maquereau infâme de maint homme et de mainte femme, poisson d’avril.” The term “poisson d’avril” is the phrase shouted out when someone falls for an April Fool’s prank.
Flemish writer, Eduard De Dene, published a poem in 1539 about a nobleman who hatches a plan to send his servant back and forth on absurd errands on April 1st. The last line of each stanza has the servant saying, “I am afraid that you are trying to make me run a fool’s errand.”
So while it’s next to impossible to say for certain when the custom of playing pranks on others on April 1 first began and who was responsible for it all, it’s a fact that April Fool’s Day has been around and acknowledged for centuries.
Historically Speaking 