The survival rate of ancient literature

[Sean Manning]

There was quite a bit destroyed during the Ottoman conquests to, I believe!

What Carlton said. The Ottoman Turks were not in the business of doing such things either. Being extremely tolerant (until the late 19th c.) they took over matters of state and taxes and did not touch local customs and religion. Which was a part of their success story in empire-building.

The quote attributed to Omar is along similar lines of the Christians in the Roman Empire attributing all kinds of horror stories about persecutions to early emperors.

Whereas the early Christians (as the 'story goes') were not actually favouring the preservation of all those ancient pagan books themselves...

Although conquest always incidentally destroys some books. Things get accidentally burned, or soldiers steal them and they get ruined in their packs, or they get casually destroyed. Sultan Mehmet may have wanted to preserve the books and buildings of Constantinople in 1453, and he did a fairly good job of it, but some of his auxilliaries seem to have disagreed. Ditto for the Crusaders in 1204.