As far as I know the longbow men were enlisted middle class citizen, not professional. Their advantage over frnech army was that they bought themselves the costly longbow which was very efficient from a strategic point of vue (fire high above your head so that it fall on the enemy).
There were very few 'professional' soldiers then. That was the whole 'militia' thing. It is a fairly recent occurence that wars are fought with only professional soldiers. It used to contain lots of militia and levys and such.
But it was often required that citizens *had* to own certain weaponry, and practice a certian amount. The Lonbowmen, though not 'professional', required lots of practice. Usually from a fairly young age.
The French (among others) did not see the advantage to the Longbow. Like the English did not see the advantage of gunnery.
The longbow had a longer range, was a much higher pull, and therefore could deliver more arrows, with more effect.
As for the 'fall on the enemy'; the advantage was range, not angle of attack. If you throw a ball 10 meters, it is fairly straight; if you throw it 50 meters, you throw it fairly high. This is just pure physics. So sure, they aimed high, but that was to get range. It should 'land' at about the same angle that it was shot. (okay, wind resistence will have an effect, but it shouldn't be too much.)
I thought that the advent of the crossbow meant the death of plate armor...
Longbows did a number on plate armour also. But neither was all *that* effective at range. (despite some cool famous examples) The difference was that it took a LOT of training to become competent with a Longbow, and a Crossbow got similar range/power results, and any old peasant could use it with little training. The difference was being able to field 50 longbowman, or as many crossbowmen as you had crossbows.
The crossbow was not a 'better' weapon than the longbow, it was just easier (and slower)
The Longbow is often referred to as the 'machine gun' of the middle ages, the Crossbow is....not. This is fairly accurately dipicted in the D20 rules I think.
Honestly, I think the Longbow should be moved to 'exotic', leave the shorbow at martial, and the crossbow at simple.
P.S. the loop effect is something which provoke some accident even today, with a bit of wind you can kill yourself with a crossbow
Sorry, I am going to have to call 'urban legend' on this one. I see NO WAY for a bolt able to penetrate steel is going to be quickly redirected 180 degrees to kill its shooter. It just way does not make sense. Please provide some linkage or something, because this just does NOT happen. A 'bit of wind'??? Think about this for a moment.... And why crossbows and not other bows??
Sorry, doesn't make any sense.
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