Agent vs. Means in Passive Sentences
Distinguish the ablative of agent (personal doer, requires ab/a) from the ablative of means (impersonal instrument, no preposition). Apply this distinction in translating passive constructions from Caesar and Cicero.
A lesson of Latin A2 — Elementary, in Passive Voice, about 10 minutes.
By the end of this lesson, you will reliably distinguish the ablative of agent from the ablative of means and apply the correct preposition (or none) in translating and composing passive constructions.
The Core Distinction
When a passive verb appears, the sentence must identify who or what performed the action. Latin uses the ablative case for both, but the rule is strict:
| Performer | Latin Construction | Example |
|---|---|---|
| Person (animate agent) | a/ab + ablative | a milite — by the soldier |
| Thing (inanimate means) | ablative alone (no preposition) | gladio — with/by a sword |
This distinction reflects the Roman view that a person chooses to act, while a thing is merely used.
Ablative of Agent
Construction: a + ablative (before consonants); ab + ablative (before vowels or h)
Used when the action is carried out by a person, animal, or personified entity:
Hannibal a Romanis victus est. — "Hannibal was conquered by the Romans." Orator ab omnibus laudatus est. — "The orator was praised by everyone." Epistula a puella scripta est. — "The letter was written by the girl." Urbs ab hostibus capta est. — "The city was captured by the enemies."
Rule: Passive verb + animate being → a/ab + ablative.
Ablative of Means
Construction: ablative alone — no preposition
Used when the action is carried out by an inanimate object, tool, or force:
Milites gladiis pugnaverunt. — "The soldiers fought with swords." Vir saxo percussus est. — "The man was struck by a stone." Hostes sagitta occisi sunt. — "The enemies were killed by an arrow." Urbs igne deleta est. — "The city was destroyed by fire."
Rule: Passive verb + inanimate instrument → ablative, no preposition.