ABSTRACT
Both the genitive and dative cases are used to show possession:
Ascanius lacrimās amīcī videt [genitive]
Ascanius sees the tears of a friend
populō Rōmānō numquam scrīptōrum cōpia fuit [dative]
there never was an abundance of writers for the Roman people (the Roman people never had …) [4.8] 1