| (a) | Perseus terram ā mōnstrīs līberat Perseus frees the land from monsters (literal separation— actual motion is expressed) |
| (b) | Perseus terram trīstitiā līberat Perseus frees the land from sorrow (figurative separation— no actual motion is expressed) |
[181.] Rule. Ablative of the Personal Agent. The word expressing the person from whom an action starts, when not the subject, is put in the ablative with the preposition ā or ab.
a. In this construction the English translation of ā, ab is by rather than from. This ablative is regularly used with passive verbs to indicate the person by whom the act was performed.
Mōnstrum ā Perseō necātur, the monster is being slain by (lit. from) Perseus
b. Note that the active form of the above sentence would be Perseus monstrum necat, Perseus is slaying the monster. In the passive the object of the active verb becomes the subject, and the subject of the active verb becomes the ablative of the personal agent, with ā or ab.
c. Distinguish carefully between the ablative of means and the ablative of the personal agent. Both are often translated into English by the preposition by. (Cf. [§ 100]. b.) Means is a thing; the agent or actor is a person. The ablative of means has no preposition. The ablative of the personal agent has ā or ab. Compare
| Fera sagittā necātur, the wild beast is killed by an arrow Fera ā Diānā necātur, the wild beast is killed by Diana |
Sagittā, in the first sentence, is the ablative of means; ā Diānā, in the second, is the ablative of the personal agent.
[182.] EXERCISES
First learn the [special vocabulary], p. 289.