The apostrophe first appeared in English sometime in the 16th century, possibly ganked into English printing from Italian or French conventions. Not much is written on the development of the apostrophe, but we know that when it first showed up in English print, it was used to signal that a letter (or several letters) had been omitted in a construction. “She’ll” is a contraction of “she will” or “she shall”; “’tis” is a contraction of “it is”; “‘zbud” and “‘sbodkins” are contractions of “God’s blood” and “God’s bodkins” and truly magnificent in the way that only 17th-century euphemisms can be.

This habit continued well into the 17th and 18th centuries, growing beyond its little garden plot. Apostrophes were sometimes used to clarify pronunciation for the reader, especially in poetry: “banish’d” was clearly meant to be spoken as two syllables to keep scansion tidy and look very Byronic, whereas “banished” could be three, particularly in some florid Drydenesque constructions. Daniel Defoe took this further: he used “cou’d” and “wou’d” in his writings to show that the “l” in “could” and “would” was silent, though I’d wager that most people who were reading Defoe likely knew about “could” and “would.”

That damn’d apostrophe was so handy that sometime around the end of the 17th and beginning of the 18th centuries, people began to use it to signal possession. It makes a great deal of sense: does “Drydens harrumphing” refer to the harrumphing of one John Dryden, or to a whole army of John Drydens making their displeasure known? We can make that clear with just one blob of well-placed ink! And so the apostrophe was liberally sprinkled among all our nouns and pronouns to mark possession.

Nouns AND pronouns, mind. So while we have the now-familiar “Dryden’s harrumphing” and “dog’s breakfast,” we also ended up with “her’s,” “their’s,” “our’s,”  “your’s,” and–yes, gird thy loins–“it’s,” which were in use as possessive pronouns through the 17th and 18th centuries. Boo, you cry, stupid, but not at all. It’s very logical: if that apostrophe was going to mark possession, then it was going to mark possession goddamned everywhere.

As a possessive marker, the apostrophe is fairly straightforward unless the base word ends in “-s,” and then everything falls all to hell. Is it “Davy Jones’s locker,” or “Davy Jones’ locker?” Yes. Is it “Jesus’s wounds?” Good lord no, of course it is not, why would you even think that? It is “Odysseus’ journey” but “Zeus’s shenanigans.” Why? Heed my words, O nerd: where were you when I laid the foundations of the possessive?

We had punctuation mania: by the 19th century, we were using apostrophes to make single letters plural, as in “p’s and q’s.” There is no logical explanation for this, apart from the fact that “ps and qs” looks odd and might result in some hapless chump spitting all over himself trying to pronounce “qs” as if it were Arabic and not KEWS. The pluralizing apostrophe also shows up by the 20th century in numbers (“alternative banjo music of the 1890’s”) and when referring to a word as a word  (“too many ‘apostrophe’s’ in this blog post”), and then later in abbreviations (“RSVP’s”) and with symbols (“&’s”), because why the hell not? Never mind that the apostrophe initially was just intended as a stand-in for elision: we wrested it away from those Europeans with all their diacritic corsetry and let it breathe. […]

And here’s the rub: the rules are continuing to change. We’re slowly losing those plural apostrophes in “the 1890s” and “RSVPs.” In Britain especially, the possessive apostrophe in some business names like “Harrod’s” and “Waterstone’s” has scarpered. These changes are themselves inconsistent. “RSVPs” but “OD’d”; “the 1890s” but “the ’90s.” […]

Considering all this, it’s not too surprising that the grocer’s apostrophe flourishes, that people still send out holidays cards signed “The Jones’s,” that even smart people confuse “it’s” and “its.” None of us–not a single one of us–has gotten the apostrophe right in every circumstance because “right” is a moving target, and that’s the thing that we lose sight of during National Grammar Day. I like grammar in all her forms (both linguistic and populist), but I will not hold her up as the eternal unchanging ideal to which all people’s intelligence and fitness must be compared.