dative of agent

The usual restriction of the dative to tenses of completed action seems to be due to the fact that the agent is represented as placed in the position of viewing an already completed action in the light of its relation to himself (interest, advantage, possession).

The dative of the agent is rarely employed with other tenses than perfect and pluperfect: λέγεται ἡμῖν is said by us P. L. 715b, τοῖς Κερκῡραίοις οὐχ ἑωρῶντο the ships were not seen by (were invisible to) the Corcyraeans T. 1.51; present, T. 4.64, 109; aorist T. 2.7.

The person by whom (not for whom) an action is explicitly said to be done, is put in the genitive with ὑπό (1698. 1. b).

The dative of the personal agent is used (1) when the subject is impersonal, the verb being transitive or intransitive, (2) when the subject is persal and the person is treated as a thing in order to express scorn (twice only in the orators: D. 19.247, 57. 10).

ὑπό with the genitive of the personal agent is used (1) when the subject is a person, a city, a country, or is otherwise quasi-personal, (2) when the verb is intransitive even if the subject is a thing, as τῶν τειχῶν ὑπὸ τῶν βαρβάρων πεπτωκότων the walls having been destroyed by the barbarians Aes. 2.172, (3) in a few cases with an impersonal subject, usually for the sake of emphasis, as ὡς ἑταίρᾱ ἦν . . . ὑπὸ τῶν ἄλλων οἰκείων καὶ ὑπὸ τῶν γειτόνων μεμαρτύρηται that she was an hetaera has been testified by the rest of his relatives and by his neighbours Is. 3.13.

a. νῑκᾶσθαι, ἡττᾶσθαι to be conquered may be followed by the dative of a person, by ὑπό τινος, or by the genitive (1402).

When the agent is a thing, not a person, the dative is commonly used whether the subject is personal or impersonal. If the subject is personal, ὑπό may be used; in which case the inanimate agent is personified (see 1698. 1. N. 1). ὑπό is rarely used when the subject is impersonal. ὑπό is never used with the impersonal perfect passive of an intransitive verb.