Origins of April Fool's Day

                    April Fool's Day is a 24 hour of devoted to innocuous, good-natured pranks, jokes and tom-foolery.  Since at least 536 B.C. when Persians "punk'd" each other on Sizdah Bedar, the 13th day of their ancient new year (April 1 or 2), this day has been reserved for such jollity.
Religious, secular, or seasonal influence?
                    However, the specific origin of April Fool's Day cannot be unequivocally attributed to ancient Persians.  In fact, so many sacred and secular observances mass around the vernal equinox (e.g., Christianity's Easter, Judaism's Purim, and Hinduism's Holi and, late in March, the ancient Romans celebrated Hilaria, to honor the resurrection of the god, Attis) that the founding of April Fool's Day remains cloaked in mystery, perplexity and supposition. But isn't this as it should be? 
                   While Christians solemnly commemorate Christ's arrival in Jerusalem, his trial, crucifixion and resurrection during Easter week, Judaism's Purim mimics Mardi Gras in its carnival-like atmosphere.  Celebrating the Jews victory over the genocidal mandate of Persian King Ahasuerus's chief advisor, Haman, through the intercession of Esther and her cousin Mordicai, Purim lends itself to unbridled good times.
                   One of the most important ancient Roman festivals, Hilaria, was a celebration devoted to the resurrection of Attis, a god of vegetation, by Cybele, or the "great mother" deity.    The weeklong festival in late March began with mourning and finished with rejoicing and feasting, where no one was allowed to show any grief or sorrow.
                   Hindus have long celebrated Holi at the advent of spring and as a commemoration of god Krishna's twice protecting King Prahlad from death, and of the annual wheat harvest.  During this merry and colorful observance, Hindus douse each other with powders of vivid colors and encourage their children to get uncharacteristically filthy.
After the Middle Ages
                  Geoffrey Chaucer first mentions April Fool's Day to western civilization in 1392.
                  The "Nun's Priest's Tale" in his Canterbury Tales tells of the fox fooling prideful rooster, Chanticleer, nearly leading to the latter's demise.  Ultimately, both the rooster and the fox fall prey to separate high jinks.
                  By 1508, French poet Eloy d'Amerval mentioned poisson d'avril ("April fish"), a likely reference to the day, in his most famous verse, Le livre de la deablerie, a robust dialogue between Satan and Lucifer about their malevolent and mischievous plans.  Three decades later, Flemish poet Eduard deDene put to verse a story about a nobleman who dispatched his servants on foolish errands every April 1.
                 Another possible factor in the day's founding might be that classical Roman and Hindu civilizations, as well as much of western civilization observed April 1 as New Year's Day until the 16th century.  With the establishment of the Gregorian calendar in 1582, the arriving new year moved to January.  Some historians suggest that because most of Europe observed New Year Day on April 1, those citizens that failed to observe the January new year were subsequently ridiculed on April 1 by those who did.  The "traditionalists" were sent on fool's errands or tricked into believing dubious claims.
                 In 1686, English philosopher and writer John Aubrey called the first day of April, "Fooles holy day" and on April 1, 1698, somebody convinced several Londoners to visit the Tower of London to "see the Lions washed."  However, neither of these incidents can be attributed to the transferred new year.  Great Britain didn't adopt the Gregorian calendar and its Jan. 1 new year until 1752.
                 By the time the 13 colonies had gained their liberty from Great Britain, April Fool's Day was indelibly etched on the calendar and in every jokester's mind.
                 It remains there.  So today, pull that prank mysteriously, savor the perplexity on your stooge's face, and have fun keeping your April's fools guessing.