In English, the possessive adjective 'my' is essentially the same thing as the pronoun in genitive. In Latin, however, the possessive adjectives 'meus', etc. are not the pronouns in genitive form, but rather they act like all Latin adjectives, agreeing with the noun in gender, number, and case.
This cause me some confusion when translating, as in §158. II. 10., 'Why were you injuring my horse?', where it appears I have two options (the key giving the former):
- ✔︎ Cūr equō meō nocēbās? (1st person possessive adjective in dative)
? Cūr equō meī nocēbās? (1st person pronoun in genitive)
But if the horse belonged to Sextus, we would not use
- * Cūr equō Sextō nocēbās? ('Sextus' in dative, which makes no sense as it is not an adjective)
- ✔︎ Cūr equō Sextī nocēbās? ('Sextus' in genitive)
§98 does state that 'the possessives ... are declined like adjectives', implying, perhaps, that using the adjective is the preferred construction. Is that the case? Or is there a choice between using the possessive adjective and the pronoun in genitive? If there is a choice: Is there a difference in meaning between the two?