The personal agent of passive verbs

Recall that when a verb is in the passive voice, the grammatical subject receives the action. In the sentence “Amphion was killed,” the grammatical subject, “Amphion,” is dead: someone else did the act. In Latin, the perfect passive tense works exactly the same way: when we read Amphion interfectus est, we know that Amphion,the grammatical subject, is dead, but we don’t know who killed him. The passive voice can be used to avoid responsibility: “Mistakes were made” admits what happened, but doesn’t identify who made any mistakes.

English can use a phrase with the preposition by to add to a passive verb the explicit personal agent: who actually did the action. “Mistakes were made by all of us” specifically says that we all did the act.

Latin can similarly use the preposition a (or ab before a vowel) to express personal agent. You know that Latin nouns indicate their function through their case ending. To indicate that a Latin noun functions with the preposition a, Latin uses a case that is new to us, called the ablative case. We’ll learn more about prepositions later in this unit, but for now all we need to know is that you use the phrase a + [noun in the ablative] to express the idea “by someone” with a passive verb. Apolline is the ablative form of the god Apollo’s name, Apollo, Apollinis, m., so when Hyginus tells the story of Amphion, he concludes it Amphion ab Apolline interfectus est.

Forming the ablative case: nouns

To form the ablative case of a noun, just add the ablative case endings to the noun’s stem, found by droping the genitive singular ending. Apollinis is the genitive singular of the third-declension noun Apollo, so we’ll add the third-declension ending to the stem Apollin-.

The ablative case endings for nouns are the following.

First declension:

Singular	Plural
-ā	is

Second declension:

Singular	Plural
-o	is

Third declension:

Singular	Plural
-e	ibus

Third declension i-stems:

Singular	Plural
-i	ibus

Let’s look at some examples of these endings in phrases expressing the personal agent. Hyginus loves to put together lists or short summaries of mythological figures who share some remarkable history, and in section 252_237, Hyginus names several figures who as infants were nourished or suckled by animals. (Note the use of the phrase “by animals” to express the agent of the passive verb, “were nourished or suckled.”) Among others, he tells us that Camilla was nourished or suckled] “by a mare” (equa, equae, f.) and Aegisthus by a she-goat (capra, caprae, f.) Since both these nouns are first-declension, he forms the ablative singular with the ending -ā.

• Camilla Metabi regis Volscorum filia ab equā.
• Telephus Herculis et Auges filius ab ceruā.

Antilochus was exposed on a mountain, where he was nourished by a dog

• Antilochus Nestoris filius ab cane.

canis, canis m. or f. is a third-declension noun, so we use the third-declension ending in the ablative form cane.

Forming the ablative case: adjectives

First- and second-declension adjectives use the same endings as first- and second-declension nouns in all their cases, including the ablative.

Adjectives with third-declension endings normally use the same endings as third-declension i-stems.

The ablative of some important pronouns

The ablative case is easy to recognize in the common pronouns is/ea/id, hic/haec/hoc and ille/illa/illud since all three pronouns use the same endings as first and second declension nouns.

Ablative forms of is/ea/id:

	Masculine	Feminine	Neuter
singular	eō	eā	eō
plural	eīs	eīs	eīs

Ablative forms of hic/haec/hoc:

	Masculine	Feminine	Neuter
singular	hōc	hāc	hōc
plural	hīs	hīs	hīs

Ablative forms of ille/illa/illud:

	Masculine	Feminine	Neuter
singular	illō	illā	illō
plural	illīs	illīs	illīs

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