374. The Dative of the Agent is used with the gerundive to denote the person on whom the necessity rests.
Haec vōbīs prōvincia est dēfendenda (Manil. 14)
This province is for you to defend.
(to be defended by you)
Mihi est pūgnandum
I have to fight.
(The need of fighting is to me.)
[cf. mihi est liber I have a book, § 373, Note)]
a. This is the regular way of expressing the agent with the second or passive periphrastic conjugation (§ 196).
Note 1— The Ablative of the Agent with ab (§ 405) is sometimes used with the second periphrastic conjugation when the dative would be ambiguous or when a stronger expression is desired.
quibus est ā vōbīs cōnsulendum (Manil. 6)
for whom you must consult
[Here two datives, quibus and vōbīs, would have been ambiguous.]
rem ab omnibus vōbīs prōvidendam (Rab. 4)
that the matter must be attended to by all of you
[The dative might mean for all of you.]
Note 2— The Dative of the Agent is either a special use of the Dative of Possession or a development of the Dative of Reference (§ 376).
375. The Dative of the Agent is common with perfect participles (especially when used in an adjective sense), but rare with other parts of the verb.
Mihi dēlīberātum et cōnstitūtum est. (Leg. Agr. 1.25)
I have deliberated and resolved.
(It has been deliberated by me.)
Mihi rēs prōvīsa est. (Verr. 4.91)
The matter has been provided for by me.
Sīc dissimillimīs bēstiolīs commūniter cibus quaeritur (N. D. 2.123)
So, by very different creatures food is sought in common.
a. The Dative of the Agent is used by the poets and later writers with almost any passive verb.
neque cernitur ūllī (Aen. 1.440)
nor is seen by any
Fēlīx est dicta sorōrī (Ov. Fast. 3.1.597)
She was called happy by her sister.
Aelia Paetina Narcissō fovēbātur. (Tac. Ann. 12.1)
Ælia Pœtina was favored by Narcissus.
b. The dative of the person who sees or thinks is regularly used after videor (seem).
it seems (or seems good) to me
Dīs aliter vīsum [est]. (Aen. 2.428)
It seemed otherwise to the gods.
Videor mihi perspicere ipsīus animum (Fam. 4.13.5)
I seem (to myself) to see the soul of the man himself.
Note— The verb probāre (approve, originally a mercantile word), takes a Dative of Reference (§ 376), which has become so firmly attached that it is often retained with the passive, seemingly as Dative of Agent.
Haec sententia et illī et nōbīs probābātur (Fam. 1.7.5)
This view met both his approval and mine.
(was made acceptable both to him and to me)
Hōc cōnsilium plērīsque nōn probābātur (B. C. 1.72)
This plan was not approved by the majority.
[But also, cōnsilium ā cūnctīs probābātur (id. 1.74)]