1. Ablatives: Agent, Origin, and Comparison
Latin 311
21 September 2011

2. Ablative of Agent 
The personal agent by whom (a person or divine being) the action of a passive verb is performed is indicated by ab and the ablative of agent.
                                                    (Wheelock, Chapter 18)

3. How to Spot Ablatives of Agent
passive verb
"ab" or "a"
conscious beings in ablative case
(i.e., people or gods)
Urbs ab malis viris delebatur.
The city was being destroyed by evil men. 

4. Ablative of Origin Aeneas Leaving Troy with his father
A.    o  Tells the biological/hereditary origin of a being.
B     o  Governed by participles signifying birth.
C.    o  Aeneas, natus Venere; Aeneas, born of Venus.
D.    o  Sometimes governed by ex or de.
E.     o  Governed by the preposition ab in the case of remote ancestry.
F.     o  Romani sunt orti ab Trojanis Latinisque. The Romans arose from the Trojans and Latinis
  Aeneas Leaving Troy with his father

5. Ablative of Comparison
The ablative of comparison is used without a preposition and is used to express a noun that is being compared to something else.The ablative of comparison is used to replace the quam in a comparative clause, and because of this the comparative adverb or adjective give this use away. Adjective use:  Ex) Domus aurea Neronis maior templo erat. Ans) The golden house of Nero was bigger than a temple. Adverbial use:  Ex) Imperator ad castra HOSTIS celerius venit. Ans) The commander came to camp more quickly than the enemy.