Which medieval weapon took more training time to become proficient with, a short bow or a cross bow? Which took more strength to use? Some writers portray crossbows as much harder to load but easier for untrained persons to hit targets with devestating effect on heavily armored opponents. Is this true?
So, in order.
The bow. I’m talking about bows in general here. To the best of my knowledge, the term “shortbow,” only dates back to the 1890s, so, not exactly a medieval weapon. This doesn’t mean that smaller bows didn’t exist for specialized purposes, just that they weren’t called, “shortbows.”
Training, again, goes to the bow. Training an archer takes much more time, and is significantly more difficult. This leads into your question about it being easier for an untrained user to put a bolt where they want it. I’m not sure if that’s true, but it is much easier to get someone up to speed on the crossbow. Getting an arrow where you want it does require more skill, training, and practice.
Strength also goes to the bow. At least for upper body strength. You’re pulling a lot of weight with every shot, and assuming your archer is getting enough to eat, they’re going to be stacked after a few years. I think I’ve said this before, but the image of a willowy archer from fantasy just does not track with the reality of the weapon. If you’re effectively pulling 80+ pounds of force with every shot, that’s going to be a workout.
“Reloading” a bow is pretty trivial. Drawing and nocking another arrow is a very simple motion, and there’s almost no mechanical considerations. Reloading a crossbow may be more complicated, depending on the arming and firing mechanisms.
Light crossbows can be rearmed by hand. You simply take the bow string and reset the weapon to fire. Heavier weapons often require mechanical systems (called “spanning mechanisms”) to rearm the crossbow before reloading. These range from a stirrup, to allow you to hold the crossbow in place while you draw the string with both hands, to lever systems, and even cranks (both Cranquins and Windlasses were used). Once the crossbow has been rearmed, the actual reload is fairly simple, but that’s a mostly academic distinction.
Saying that it’s harder to reload a crossbow is fair. A little bit of an abstraction, but that’s entirely fair. They do have a much lower cyclic fire rate. With a bow, you simply need to draw another arrow, nock it, draw, and you’re ready to fire. With a crossbow, you need to rearm it (which may be simple, or it might not be), draw and load the bolt, and then you’re ready to fire.
So, when you have crossbows that are delivering force a human archer could not replicate, then, yes, that’s going to impact a target with more power than you could get from a bow. There’s a lot of factors here that I’m glazing over, so, this doesn’t mean that a crossbow will always, automatically, hit harder, and penetrate armor more easily, with heavier designs, especially ones with crank systems, that’s certainly possible.
So some basic physics, when you launch an un-powered missile (doesn’t matter an arrow, bolt, or bullet), it will lose velocity and be affected by gravity (called drop) as it travels. This means, at shorter ranges, these weapons will exhibit better armor penetration, than they will at a distance. So, if you have a character in fairly tight quarters, like a city street, firing a crossbow, it might have better armor penetration than you’d see from a longbow on a ridge.
In fact, crossbows saw most of their use in urban environments, while bows were more common in rural areas, and among standing military forces. The reason is not just tailoring the right weapon to the right situation, but also economic; crossbows were expensive. Even the light crossbows were more mechanically complicated than a bow, so it was easier to produce low quality bows, than low quality crossbows. Cities, with significant economic and production resources could afford to outfit their armories with crossbows, but equipping a village armory, meant you’d probably have to do without. This also meant that crossbows saw use among mercenaries, since they’d be paying for their own gear. European armies transitioned from bows to crossbows at varying points starting in the 12th century. By the 15th century, almost all of Europe had transitioned over, with the notable exception of the British.
Early firearms began appearing in European warfare, in the 14th century. There’s actually a timeframe where the choice would have been between primitive muskets, and crossbows. This persisted into the early modern era, as well. During this period, the crossbow would have been the an alternative with better armor piercing capabilities than those early guns. Also, for awhile, better accuracy and faster reloads. Once you move out of the middle ages, and into the early modern period, firearms start improving beyond the crossbow, but for awhile they both had a battlefield role.
It’s also worth remembering that in these situation, most soldiers would have carried a sword as their sidearm. So, it’s not like your character would have only carried a bow or crossbow, they also would have had something if they ended up in melee.