Reddit reviews Caesar in Gaul and Rome: War in Words

>if you (as a Roman citizen) place a high value on glory through combat, does it not follow that this glory would not be enhanced by describing one's vanquished foes as miserable and cowardly, and therefore not very difficult to defeat? That the greatest glory would be achieved by defeating an opponent of great virtue, strength and honor?

Yes, exactly. Caesar in the Bellum Gallicum describes the Gauls as surprisingly (to a Roman audience) clever and tenacious, and takes care to point out that they don't fight like gentlemen should (they hide in the forest instead of lining up for battle, for instance). It took longer to subdue Gaul than Caesar anticipated, and some scholars think that the Bellum Gallicum was written and published year-by-year as a way of explaining what exactly was going on up there. (For more, check out Riggsby's Caesar in Gaul and Rome.)

I know you said you're looking for free resources, but this is a good book on the subject.

https://www.amazon.com/Caesar-Gaul-Rome-War-Words/dp/0292726171