Topic summary
Saxon genitive
Extracted from the Wikipedia article English possessive.
For nouns, noun phrases, and some pronouns, the possessive is generally formed with the suffix-'s, but in some cases just with the addition of an apostrophe to an existing s. This form is sometimes called the Saxon genitive, reflecting the suffix's derivation from Old English. However, personal pronouns have irregular possessives that do not use an apostrophe, such as its, and most of them have different forms for possessive determiners and possessive pronouns, such as my and mine or your and yours.