Fools, April and literature have shared a long and dangerous tradition. When St. Chrysostom lastingly defined the Fool in the third century as "he who gets slapped," the slapping had already been going on for some time. Dialogues from ancient Greece and Rome show professional buffoons like 'Philip the laughter-maker' topping philosophers who should know better, like Socrates. The best slapschtick was collected, and jest-books of routines and one-liners -- literal 'best hits' -- were treasured reading for the Fools on the banquet circuit.
Traditionally, Fools worked for the philosopher-king-pope power groups, but it was not uncommon for noble households to have resident Fools in the Middle Ages -- sort of a human sitcom. Those who could not afford a full-time Fool of their own could be a part-time one themselves. Many cultures and religious cults sanctioned days of folly, usually in mid-Winter or early Spring.
Historians think that April 1st became April Fools' Day in 1562, when Pope Gregory introduced the new Christian calendar. This moved New Year's Day, and the Twelfth Night foolery associated with it, from April 1 to January 1st; those who resisted or didn't know about the shift and still held their New Year's party on April 1st apparently began to be called April Fools.
In the medieval Christian Church, folly celebrations took the form of the Feast of Fools or the Feast of the Boy-Bishop, a tradition in which the lower-downs, such as the junior clergy or the choirboys, were allowed to humiliate the higher-ups. The authorities tried their best to control the mayhem -- "not more than three buckets of water at most must be poured over the head of the precentor stultorum at Vespers" -- and eventually they managed to enforce a ban in the late fifteenth century.
All this meant was that people went elsewhere for their folly. Records of the Middle Ages and Renaissance are full of references to the various fool-societies and Lord of Misrule festivities that were popular throughout Europe. These were boys-night-out institutions, much feared and tolerated by the ruling powers, even though the satire often got vicious. The pragmatic Louis XII arrived at an agreement with his antagonists that they could say whatever they wanted about him or his court, as long as they left his wife alone. Thus the household truth of the ages was in the 16th century elevated to royal decree: 'He must be wise who plays the husband.'
In literature, the Fool had his finest hour during the Renaissance. The Praise of Folly by Erasmus takes its satiric slap at pretty much all of us, and whatever Shakespearean plays do not have comic Fools have tragic ones wishing that they weren't. The most famous novel in modern fool-literature is Katherine Anne Porter's Ship of Fools, published on April Fools Day, 1962. Porter took her title from a moral allegory of that name published in the fifteenth century. With these roots, it isn't surprising that Porter's novel about the slide of the Western world into WWII belongs to a more earnest branch of the folly tree. Never shy, Porter described her book as being about "the constant endless collusion between good and evil." Her passengers ride the Vera, bound for the horrors of Hitler's Europe, but the truth-boat is not long out of port before we realize that it already carries the greater horror of human nature. The book and then the movie were popular when they came out, although many critics scoffed at the notion that Porter's hindsight moralizing was a brooding novel of ideas.
Undaunted, the Fool tradition sails on. You can find an online Christian magazine at ship.of.fools.com. If you are untroubled by salvation or irony, you can invest at Fool.com. You can listen to the Swedish hip-hop trio, Ship of Fools -- if you didn't get enough of the metaphor from John Renbourn, or Erasure, or the Grateful Dead, or the Cowsills. You can play on the Dungeons & Dragons Ship of Fools, or watch plays on the Dutch performing arts boat Ship of Fools if they anchor at a port near you.
You can read a half-dozen contemporary novels called Ship of Fools, or a so-called short story by Ted Kaczynski. The Unabomber's attempt to pronounce upon folly from his prison cell seems to unexplode in his face at the last, lame line: "The ship kept sailing north, and after a while it was crushed between two icebergs and everyone drowned." Thus, the other hometruth of April and the ages: 'He must be a fool who plays the wiseguy.'