In the Nun's Priest's Tale
(written around 1392), Chaucer tells the story of the vain cock Chauntecler who falls for the tricks of a fox, and as a consequence is almost eaten. The narrator describes the tale as occurring:
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
Some scholars have suggested this is a veiled reference to April 1st, since thirty-two days "Syn March bigan" (since March began) would be April 1. It is intriguing to think that Chaucer might have chosen this date purposefully, setting the tale on April 1st because of the tradition of tricks and foolery associated with the day. It would be appropriate for a story of a foolish cock and sly fox.
If it is a reference to April Fool's Day, then it would be the earliest recorded reference to the day. However, Chaucer's choice of words is extremely ambiguous, and most scholars think he meant May 3, since that would be "thritty dayes and two" after March "was complet."
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