A question! Of grammar, and history!

[desperance]

If - as I sort of puzzled out on my fingers long ago, lacking any formal education in the matter, and have simply assumed to be the case ever since, as one does - the possessive 's is indeed a contraction of "his", as in "Chaz Brenchley, his book" going down to "Chaz Brenchley's book" - then has there ever been a time or a schismatic group or a pedant or a theorist or an argument wherein there was a parallel feminine form, 'r standing for "her"? "Mrs Brenchley'r book" would be awkward in the mouth, but on the other hand and if not, there must have been an abrupt and awkward shift at some point from "Mrs Brenchley, her book" to the masculine contraction. Mustn't there...?

Now I'm going to watch American football. When I come back, I expect someone to have put me right.