[Legate of Amon Lanc]

Alright, allow me to add a short excursion about one thing that somewhat emerged on its own as I was reading: Biblical parallels.

It started when I noted the character of the grey mare being the "reasonable one" (if not straightaway the wise one), especially the way it was underlined when Giles and the knights were about to approach the dragon's lair. That reminded me of the story of Bileam in his donkey in Numbers 22. There, Bileam is also riding off to do something stupid (notably also at the request of a corrupt king), is riding oblivious to a danger (there represented by a sword-wielding angel blocking the road) that the wise she-donkey perceives, unlike her master. Eventually, the donkey speaks to rebuke her master.

There are of course notable differences in the stories, but you could say they contain the same patterns (and it is just as well possible that the story of Bileam may have been one of Tolkien's conscious or unconscious sources of inspiration). The mare in Giles's story does not speak aloud, but we see her thoughts in direct speech. The stupid ones are in Giles's story rather all the knights than Giles himself, so they are Bileam more than Giles is.
At the same time, however, Giles is actually a lot like Bileam himself. In that particular Biblical story, Bileam is essentially the good guy. I already noted the parallel between Augustus Bonifacius and the evil king Balak. And just like Giles sets off with the premise to fulfil the king's command and slay the dragon, Bileam sets off with the premise to fulfil Balak's wishes and set a curse upon the people he wished to destroy, but ends up blessing them instead.

The second thing that struck me as similar were the dealings between Giles and the king. Again: you could say that the "man of the people defies the monarch and becomes a hero, founding his own kingdom" is a trope we find in many stories (to stay close, one could mention King Arthur - even though that also is already n-th down the line of being built on previously existing myths). But of the more significant stories in Tolkien's cultural environment, it is also reminiscent of the story of David versus Saul. You could point out many similarities, such as Giles recruiting the "leftovers" or the promising young lads (a very Davidic trope), being the "popular king" versus the by-law one, etc. But it was notably the dynamic between them - specifically the way Augustus Bonifacius speaks - that reminded me of the Biblical Saul a lot. The outburst of anger, followed by the desire to just kill Giles in person after an unsuccessful military campaign just gave me a very similar vibe. And at the same time, Giles shows a very "Davidic" attitude by telling the king to just go home and cool his head, just like David refused to kill Saul when he had the chance.

These are perhaps a stretch and I absolutely do not want to put an equation between (these parts of) the story of Giles and the abovementioned stories. Nonetheless, at the very least you can say that they draw upon the very same tropes (the David thing) and it is possible, if not probable, also given Tolkien's erudice and background, that he got either unconsciously or consciously inspired by them. And I especially like the case of the Bileam story, because if you asked who was the hero of that one, the answer should truly be "Why, the she-donkey, of course!"