How do I understand "victís" and "imperitátum" in this sentence from Livy XXI?

Question

In Róma Æterna (second volume of Lingua Latína per sé illustráta), p. 209, in a discussion of Hannibal adapted from Livy book XXI, contains the following sentence:

Odiís etiam prope májóribus certávérunt quam víribus, Rómánís indignantibus quod victóribus victí ultró ínferrent arma, Pœnís quod superbé aváréque créderent imperitátum victís esse.

I'm confused both by victís and by imperitátum (though more by the latter than the former).

My impulse would be to make the infinitive victós esse, with an implied sé somewhere in there, so that it would agree with the accusative + infinitive construction. I can easily imagine, though, that victís has been attracted by Pœnís into the ablative. If that's not what's going on, though, does anybody have any ideas?

More confusing to me (or at least less productive of possible explanations) is imperitátum. The only neuter noun in the sentence is arma, which doesn't match in number (and also arma imperitáta doesn't make any sense), so if it's a participle I don't see what it could be referring to. But there aren't any verbs of motion, so it can't be a supine either.

Any ideas?

Answer 1

The one piece of the puzzle you're missing is that impero takes a dative for the person being commanded: this explains victis, as agreeing with an implied "them" (sibi).

Imperitatum is an impersonal passive: literally, "they believed it to have been commanded to them", i.e. "they believed they had been commanded". The syntactic issue here is that since impero takes a dative object, it can't be passivized normally, so this impersonal construction has to be used instead.