So, this question was triggered by my reading Stephen Turnbull's book on the Gempei War, when he says that he thinks that the yumi, or Japanese longbow, had an effective range of 10 meters against armor, 20 unarmored. Which seemed horrifyingly low to me.
I mentioned this to a friend who knows a good deal about the Crusades, and he said that, yes, he thought war bows in the middle east at the start of the Crusades were also very weak, and they didn't become dominant in the region until the fourteenth century.
And a second friend mentioned the weakness of the bow in the classical mediterranean area, with slings being superior for military purposes.
But the wood-horn-sinew composite bow - the 'Hunnish Bow,' as I've heard it called, or 'steppe bow' - dates back to, according to Wikipedia, at least the second century BC, and some versions apparently more than a millennium further back. It was certainly terrifying Europe in the 5th century CE when the Huns arrived, and I assume that when the Seljuk Turks came off the steppe to take over Persia, they were using it, too. And it was, by all accounts I've read, a terrifyingly powerful, long-range, armor penetrating weapon of marvelous efficiency, with people claiming it can penetrate armor at a hundred meters and hit an unarmored target at four hundred meters or more.
So why wasn't the rest of the world, the world off the steppe, using it? I mean, maybe it didn't reach the classical world until the Huns brought it there, but why weren't the Japanese and the Ayyubids and the Byzantines and everyone else in the faintest contact with the steppe using steppe bows, instead of their apparently-inferior weapons? In particular, even if the common soldiers couldn't afford them, why weren't their aristocracies using them, if they were using bows anyway and the steppe bow was so much better?
References with regards to quality:
Vegetius, writing in the 4th century:
A third or fourth of the youngest and fittest soldiers should also be exercised at the post with bows and arrows made for that purpose only..." and, later, "Soldiers, notwithstanding their defensive armor, are often more annoyed by the round stones from the sling than by all the arrows of the enemy.
But Maurice, writing in the 6th century, after the Hunnish wars:
Apart from the foreigners, all the younger Romans up to the age of forty must be required to possess bow and quiver, whether they be expert archers or just average... unskilled men should use lighter bows. Given enough time, even those who do not know how to shoot will learn, for it is essential that they do so.
Quoting Stephen Turnbull, "The Gempei War 1180-85: The Great Samurai Civil War", location 353 on my Kindle:
For all its length the Japanese longbow had nothing like the power of the bows wielded by the mounted warriors from the steppes of Central Asia. The maximum effective range of a Japanese arrow was unlikely to be more than about 20m, and the preferred distance for inflicting a wound or killing an opponent through a weak point in his armour was little more than 10m.