There is an amazing use of the ablative case in Latin called the “ablative absolute” that is the very picture of the economy of the language. It can compress an entire story into only a couple of words. It is a type of participial phrase complete with head noun and participle, both in the ablative. What distinguishes it from the participial phrases that you just read about is that it sits independently of the main clause it goes with.
Here are two examples to examine:
Hostēs captīs occidimus. (After the enemies had been captured, we killed them.)
Hostibus captī s, castra mī vimus. (After the enemies were captured, we broke camp.)
In the first example, “the enemies” appears twice. Since they are both head noun in a participial phrase and at the same time direct objects of the main verb, they need to be represented twice: once in the expanded participial phrase, then again in the main clause. Rather than repeat “the enemies” twice, it sounds better to replace one occurrence with a pronoun.
In the second example, there are also two actions, killing and breaking, but the enemies are only involved with one of the verbs, namely the killing. Since the enemies have — at least grammatically — nothing to do with the main clause, they are absolute (ab, “away”; solū tus from solvī , “to turn loose”). That is why the head noun, hostibus, and the participle pertaining only to them, captī s, are in the ablative and set off from the rest of the sentence.
An ablative absolute phrase can be translated nearly the same way as ordinary participial phrases. The simple adjective and relative clause approaches are awkward, stilted, or make no sense.
Simple adjective: The enemies having been captured, we broke camp.
Relative clause: The enemies
whohad been captured, we broke camp.
Afterthe enemies had been captured, we broke camp.
Sincethe enemies had been captured, we broke camp.
Coordinate clause: The enemies were captured,
andwe broke camp.
Althoughthe enemies had been captured, we broke camp.
Rēs ipsa loquitur. (“The matter speaks for itself.”)