This interesting article by James Glanz (hat tip: HC) is also a bit of a mess. Some historians now think the English were not quite so outnumbered at the Battle of Agincourt (Oct. 25, 1415) as has long been assumed. Other historians disagree. Only military history buffs are going to be able to get really worked up about this.
The article's messiness comes from another point: the alleged similarities between the Hundred Years War and contemporary counterinsurgency conflicts. Really? Yes, like, riilly. I'm no expert on medieval warfare, but I think this kind of analogy has to be approached with extreme caution. The article mentions Conrad Crane, military historian and lead author of the not-entirely-uncontroversial revised U.S. Army and Marine Corps counterinsurgency field manual (see the symposium on it in Perspectives on Politics, June 2008), "some of [whose] own early historical research involved a comparison of strategic bombing campaigns with attacks on civilians by rampaging armies during the Hundred Years’ War, when England tried and ultimately failed to assert control over continental France." I haven't read Crane's work, but I assume he points out that attacks on civilians in the Hundred Years War were partly motivated by the fact that the armies, and the roving bands of armed men that hung around and sometimes supplemented the armies and were sometimes indistinguishable from them, needed to seize food and provisions from local civilians to continue campaigning. (There was also no doubt a good deal of rape and pillage as well.)
Yes, as Mr. Glanz suggests, the Hundred Years War could be seen as a kind of civil war into which an outside power "intervened," except the "outside" power -- England -- had long claimed dynastic title to, and in part controlled, sections of France. Moreover, the Burgundians were not just a "faction," as this article says; Burgundy was a separate polity, distinct from the kingdom of France, from the late 14th century, and a very powerful one well into the 15th century. Do these historical nitpicks affect the contention that there are parallels between the Hundred Years War and contemporary counterinsurgencies? I'm going to duck that for now. Those who are interested can ponder the question at their leisure. (And see also Alexander Downes, Targeting Civilians in War, which I mentioned previously in a comment thread here.)