Evolution of apostrophe as possessive.

I heard somewhere - or dreamt it - this explanation of why an apostrophe and s are used in English to denote possession. Can anyone confirm or refute?

Once upon a time, possession was indicated by "his" only. So you would say, "John his horse" instead of "John's horse" or "John his children" instead of "John's children". Apostrophe s was really a contraction of the word 'his'. Since women weren't considered to own property in that time, there was no corresponding apostrophe r: "Jane her children" becoming "Jane'r children."