Note: Even though I am publishing this on April Fools Day, and about April Fools Day, I swear it is all true. Well, not so much true as accurate. That is, stuff here may be made up, but it wasn't made up by me. But, because I'm rushing to get this out today, I won't bother with adding any sources. Or with things like poof-reading.
While some sources say that April Fools Day, sometimes also called All Fools Day, began around 1700, it's pretty clear that it's older than that. But in the 1700s and 1800s April Fools Day was all about “making an April Fool”, that is turning a person into an April Fool. One source bragged that someone had “made over a hundred April Fools” (not a direct quote, just from memory). In other words, he tricked over a hundred people. While today, the trick can be all sorts of things, at that time the focus seemed to be almost exclusively sending people on foolish errands (and may well be the origin of the “fool's errand” as a common idiom). (Note: I just made up that connection about “fool's errand” and while it could well be true it does mean I lied up at the top there where I said I wouldn't make anything up. Sorry.)
It was apparently such a big problem that some sources describe the difficulty in getting people to perform errands on April first, on the grounds that it was probably just an attempt to make them into an April Fool.
One claim I see in a few sources is that April Fool's Day came about because of the change in Europe from the Julian to the Gregorian Calendar. New Year's Day was apparently frequently celebrated on March 25th or thereabouts and somehow this means that people who were celebrating the New Year on this schedule were out-of-date, and therefore fools. There's a few problems with this. For one, there seem to be sources that refer to the April Fool custom before the Gregorian calendar was adopted (for example, a 1539 Flemish source that I read a convincing description of somewhere). The other problem is that under the Julian Calendar, New Year's Day was actually January first also. The practice of celebrating New Years Day in March was a local custom that was just as out-of-step with the real calendar before this change as it was after.
|Clipped from Theorica Della Compositione Dell' Vniverso Et Delle Cavse Della Nvova Riforma Dell' Anno, 1582|
It has something to do with the Gregorian calendar.
|The Rape of the Sabine Women, Sebastiano Ricci, ca. 1700|
(There are a bajillion paintings of this event. Seriously you say "rape" and painters are like "I'm there".)
|"Scomber Le Maquereau", Poissons de Mer, Aalbert Flamen, ca. 1660|
|From Histoire de France. Le Blog La France pittoresque (Not sure about actual origin.)|
At least one source says that “poisson” could be a confusion of the word “passion”. Unfortunately this has nothing to do with the movie Passion Fish (as far as I know), so there's no excuse for me working that in here. But the suggestion here, which actually does relate to April Fools Day, is that this is a reference to the Passion of Christ, with Jesus cast into the role of the fool, as he is bounced around Jerusalem from one authority to the next on a wild goose chase (or, one might say, a “fool's errand”.) This of course all took place sometime in the vicinity of April first. Being an old source, they naturally blames all this on the Jews rather than the Romans. Therefore, April Fools day was cast as a Jewish celebration of the success in tricking Jesus. In which case April Fool's Day is basically a leading cause of the Inquisition. (Note: that last remark was 100% made up by me, and bears no relationship whatsoever to reality.)
In a similar vein, some have blamed April Fool's Day on the Jews by tying it to the fool's errand that Noah (you know, the one with the flood) sent that first dove on, before there was any land to find. Which conveniently makes a nice segue between religion and birds.
|One of many types of cuckoos|
From Histoire naturelle des oiseaux d'Afrique, vol. 5, 1799, Le Vaillant, François
Yet another story claims that April Fools Day can be blamed on the cuckoo (or cuckow) bird. The cuckoo is a brood parasite — a bird which is too lazy to raise its own kids, so it lays them in the nest of some other bird, and lets that bird raise them. Just to add weight to this theory, in some parts of England an April Fool was called an “April gowk”, where “gowk” is another word for the cuckoo. The birds typically lay their eggs around April First, and so somehow (don't ask me how, I didn't make this part up), this leads to a holiday in their honor. A holiday to celebrate child abandonment. Which goes right along with the theories about rape and prostitution.
So the majority of these theories seem to be oppressive of women, either tying the holiday to rape, prostitution, or a mom abandoning her child. And some of the other theories seem to be anti-semitic. Does this mean that we should reject this holiday, as it is clearly about oppressing somebody?
Or does it just mean that people that invent stories to fill in missing history are jerks?
Maybe we're fools for falling for it.
[But seriously, that closing sentence was not some sort of “gotcha” admission of this all being a trick. This stuff is all real, I swear. Except for the parts that aren't that I mostly mentioned in there. Mostly. I really did look at a whole bunch of sources. Here's one that's an excellent summary, just to make you feel better: Popular antiquities of Great Britain, 1877, sir Henry Ellis.]