I assume many of us grew up admiring the two factions of Rangers from Tolkien's novels. An interest in that sort of fantasy was actually what drove me into the hobby of real-world history. I've come to notice over the years, though, that all of the medieval weaponry and armor and accounts I've encountered are either about full-on pitched battles or civilian life and self defense. There doesn't seem to be much material in the common eye pertaining to that middle ground of scouting, exploring, asymmetrical warfare, and other such martial endeavors that would not take place on a battlefield.

We see this kind of thing prominently in the colonial period; Rogers' Rangers are justifiably famous, the conflicts against native tribes were of this sort, and Americans used irregular "light" forms of combat and reconnaissance in both the F&I War and their own War for Independence. But when it comes to the medieval period, the only thing I'm remotely aware of that fills the same niche are the anachronistic legends of Robin Hood.

Do any of you know of any good sources on this kind of warfare in the medieval period? Did it exist, or is it a result of modern people translating modern warfare onto history? If it did exist, I'm particularly interested in the material culture associated with it.

A very good read.

https://boydellandbrewer.com/special-operations-in-the-age-of-chivalry-1100-1550.html

Plus, there are literally tons of material on sieges, chevauche and other military situations that were not pitched battles. The latter were very few and far between compared to the former.

You might get some direction from the free reading list at: https://deremilitari.org/

I imagine that there were plenty of Welsh guerrilla fighters when Edward I and Henry IV were marching around in Wales.

The Welsh under/against Henry IV were organized by the more wealthy under Owain Glyndwr's bid as the proper Prince of Wales. What is described in Shakespeare's Henry IV is actually fairly accurate as to the doings on.

So anyway, not so much guerrilla tactics by the Welsh but rather ordinary warfare of the time and place. Read on Glendower's history and in going back, start with the Plantagenent reign, 12th century. You'll come across fairly sophisticated tactics as armies on both sides, even then. A lot of the fighting and actions fairly well chronicled.

As to the American colonial wars and the revolution, the colonists actually lost in a stand up fight on Breed's Hill, pushed back by British troops, who were advancing up a hill in sweltering heat against fortification. The shots heard around the world at Lexington and Concord devolved into the British being sniped at all the way back to the ferries at Charlestown, somewhat met and relieved by British troops under Hugh Percy (a descendant of the same Percy family that fought allied to Glendower against Henry IV). Whatever the colonists learned of harrying the English after Concord was lost in the months to follow and were fairly routed on Breeds hill by a lesser force of British troops (at that battle). They might have done well to act guerrilla before the British troops landed on that point of land. The colonists had quickly established an unsustainable promontory and lost that bid.

At roughly the same timeline, we have Roger of Ranger fame rolling into the Queens Own rangers comprised of largely colonists loyal to the crown. So no real guerrilla tactics there either.

Missouri's partisan rangers, while colorful in the history books had little effect on the American Civil War and aside from very few guerrilla actions (comparatively) throughout history, imo, were a nuisance but not really a deciding factor in the big picture of things.

Cheers
GC