First let’s all join in a hearty curse of the grammarians who inserted the wretched apostrophe into possessives in the first place. It was all a mistake. Our ancestors used to write “Johns hat” meaning “the hat of John” without the slightest ambiguity. However, some time in the Renaissance certain scholars decided that the simple “s” of possession must have been formed out of a contraction of the more “proper” “John his hat.” Since in English we mark contractions with an apostrophe, they did so, and we were stuck with the stupid “John’s hat.” Their error can be a handy reminder though: if you’re not sure whether a noun ending in “s” should be followed by an apostrophe, ask yourself whether you could plausibly substitute “his” or “her” for the S.
My correspondent called this theory an urban legend, and pointed me toward the Wikipedia article “Saxon genitive.”
I am not one of those people who dismisses Wikipedia as wholly unreliable. It’s my first choice when I’m doing a quick bit of research. But it’s often not a satisfactory substitute for professionally written and edited research.
Here’s the relevant passage from the “Saxon genitive” article:
In Old English, -es was the ending of the genitive singular of most strong declension nouns and the masculine and neuter genitive singular of strong adjectives. The ending -e was used for strong nouns with Germanic Õ-stems, which constituted most of the feminine strong nouns, and for the feminine genitive singular form of strong adjectives.
Gender Singular PluralIn Middle English the -es ending was generalised to the genitive of all strong declension nouns. By the sixteenth century, the remaining strong declension endings were generalised to all nouns. The spelling -es remained, but in many words the letter -e- no longer represented a sound. In those words, printers often copied the French practice of substituting an apostrophe for the letter e. In later use, -'s was used for all nouns where the /s/ sound was used for the possessive form, and the -e- was no longer omitted. Confusingly, the -'s form was also used for plural noun forms. These were derived from the strong declension -as ending in Old English. In Middle English, the spelling was changed to -es, reflecting a change in pronunciation, and extended to all cases of the plural, including the genitive. Later conventions removed the apostrophe from subjective and objective case forms and added it after the -s in possessive case forms. See Apostrophe: Historical development
Strong masculine -es -a
Weak masculine -an -ena
Strong feminine -e -a
Weak feminine -an -ena
Strong neuter -es -a
Weak neuter -an -ena
In the Early Modern English of 1580 to 1620 it was sometimes spelled as "his" as a folk etymology, e.g. "St. James his park"; see his genitive.
The body of this passage presents the theory which my correspondent and many other writers on the Web prefer, but the final sentence referring to the “his” theory as “folk etymology” does not contradict what I wrote. Indeed the idea that the S at the end of a possessive form stood for “his” was a folk (that is, false) etymology in the late 16th and early 17th century.
The article cites several references, but none for the etymology of the genitive apostrophe.
But it does link to the Wikipedia article “His genitive”
As printing became more widespread, and printed grammars informally standardized written English, the "-s" genitive (also known as the Saxon genitive) with an apostrophe (as if an "his" had been contracted) had gone to all nominal genders, including nouns that previously had an unmarked genitive (such as "Lady" in Lady Day"). This remains the general form for creating possessives in English.
This is clearer and more succinct, and does not dismiss or affirm the "his" theory; but it also contains a cited source, a classic article to which most writers on this issue refer: Elizabeth S. Sklar: "The Possessive Apostrophe: The Development and Decine of a Crooked Mark." College English, vol. 38, no. 2, pp. 175-183.
Using my university library account to read the article on-line, I find, on page 178 of that article:
A more serious impediment to the application of the apostrophic genitive to the plural forms of regular nouns, however, was the fact that many grammarians considered the procedure illogical and therefore improper. Most grammarians by this time felt that the genitive singular apostrophe had an historical justification: it was regarded as a mark of elision representing sounds which had, in the earlier stages of English, been present and pronounced. Theorists did not, of course, agree on precisely what as elided; some held that the ’s was a contraction for the pronoun in the his-genitive construction, while others, Priestly and Lowth among them, contended that the apostrophe took the place of the e in the Old and Middle English genitive singular affix es. Actually, neither explanation is entirely satisfactory, but both served the necessary function of justifying the presence of the apostrophe in genitive singular constructions and thus hastened its acceptance by grammarians. If they disputed exactly what sounds were elided, they were in accord on the most important particular: something was missing and the apostrophe quite properly took its place.
A footnote on the bottom of the same page continues:
The proposition that the retrenched sound represented by the apostrophe is the e from the old es genitive affix is attractive in its simplicity, but historically improbable. In the first place, over two hundred years had elapsed between the disappearance of the inflectional e and regular use of the apostrophe as a genitive marker; that is, the apostrophe would have to represent a sound heard by no speaker and a letter seen by few. More important is the fact that the nominative plural affix, which was identical to the genitive singular in late Middle English, did not evolve in any systematic way into an apostrophic construction. It is more likely that the presence of the apostrophe is in some way accounted for by the his-genitive construction, which chronologically preceded the advent of the possessive apostrophe; but as Den Breejen shows, the pronomial genitive construction was rather limited in distribution—it was by no means the only, or even the most common, means of expressing the genitive relationship. For a discussion of the evolution of the his-genitive construction, see H. O. Wyld, A History of Modern Colloquial English (London: T. Fisher Unwin, Ltd., 1920), pp. 314-336.
So the article cited as an authority in the Wikipedia “His genitive” article actually argues against the position taken in that article. This is a major problem with Wikipedia. When it cites actual scholarly sources, they are often unavailable for checking on the Internet. You have to have special access to check them.
Then I looked at the Wikipedia article “Apostrophe” and found that it briefly mentions the “–es.” theory but not the “his” theory. These three articles would have benefitted from having a single editor bring them into line with each other, and with their own footnotes.
Further checking in Google Books shows that authorities have been arguing for and against each of these theories since the 18th century.
There are plenty of serious writers on language who provide evidence for the “his” theory, like John Algeo and Thomas Pyles in The Origins and Development of the English Language:
That genitive –s was confused with his is shown by the occasional use of his with females, as in “Mrs. Sands his maid” (OED, 1607), and by the mixture of the two spellings, as in “Job’s patience, Moses his meekness, Abraham’s faith” (OED, 1568). In the latter example, his was used when the genitive ending was pronounced as an extra syllable, and ’s when it was not, the apostrophe also suggesting that the genitive –s was regarded as a contraction of his. Other spellings for both his and the genitive ending were is and ys, as in “Harlesdon ys name” and “her Grace is requeste,” that is ‘her Grace’s request’ (Wyld 315).
His (with its variants is and ys) was much more common in this construction than her or their. The his-genitive, whichever pronoun is used, was most prevalent with proper names and especially after sibilants, as in Mars, Moses, Sands, and Grace, an environment in which the genitive ending is homophonous with the unstressed pronunciation of his. Although the his-genitive in Old English must have been the sort of topic-comment construction cited above, its early Modern English frequency was certainly due, at least in part, to a confusion of inflectional –s and his. The construction has survived, archaically, in printed bookplates: “John Smith His Book.”
Scholars have disagreed about which of these two theories is correct since the 18th century, and will probably continue to disagree. I suppose it’s possible some early writers used the apostrophe to stand for “his" and others meant it to stand for “-es.” My own note on the subject was a little too sweeping. I’m mainly interested in getting my readers to remember to use the possessive apostrophe, so I prefer to discuss the theory that will best help them do so. I’ve amended the entry as follows:
First let’s all join in a hearty curse of the grammarians who inserted the wretched apostrophe into possessives in the first place. It may well have been a mistake. In Medieval English possessive nouns ended with an -ES or -YS. Eventually the vowel before the S disappeared, and we were left with forms like “Johns hat.” Some 17th-century writers took the result to be an abbreviation and decided that the simple “s” of possession in a phrase like “Johns hat” must have been formed out of a contraction of the more “proper” “John his hat.” One theory is that since in English we mark contractions with an apostrophe, some scholars did so, and we were stuck with the stupid “John’s hat.” Their purported error can be a handy reminder: if you’re not sure whether a noun ending in S should be followed by an apostrophe, ask yourself whether you could plausibly substitute “his” or “her” for the S.