Alexandria was also hard hit many times in between 48 BC and 364 AD, but it's doubtful many scrolls survived the initial fire (if the fire actually involved the Great Library) as the scrolls were stacked and highly combustible. The library complex was rebuilt (if actually destroyed), which probably wasn't too hard because it reportedly had one reading room, several meeting rooms, and one hall with scrolls stacked along the wall. The entire area it was in, the Bruchion district, was said to have been turned into a desert by a brutal war in 270 AD, so perhaps there's little need to proceed. Anyway, in episode 13 NGT says: "Estimates vary on the total number of scrolls. They range from 500,000 to nearly a million." Wow. He knows how many scrolls it had to within a factor of two, while scholars can't quite decide if it still existed after 48 BC, or if the fire in 48 BC actually burned the library at all, or whether there were really two libraries from the start. We do know there was a daughter library that at one time contained 42,800 scrolls, according to the librarian, and Seneca says only 40,000 scrolls were destroyed in Caesar's fire. Yet Mark Anthony claimed to have added 200,000 scrolls from a different, non-Egyptian library as a present to Cleopatra, but that was probably mostly his pr0n collection. NGT: "So in the 4th Century AD when the mob came to destroy the Library and the genius of classical civilization, there weren't enough people to defend it." We can be certain that such an event never took place because a period source states that the temple complex that was destroyed in 391 did not still contain a library, and none of the people involved on either side mention any scrolls or books being destroyed, and the first claim of such destruction dates back only to the 1780's, which is apparently were Sagan picked it up (Gibbon's "Decline and Fall of the Roman Empire.") Here's one pretty good page on it, but there are many others. What we know is sketchy, at best, which isn't surprising considering how far back in antiquity we're going. One thing to always keep in mind for studying that era (and up until the industrial age) is that the people were, by our standards, innumerate or sloppy when it came to large numbers, using them in the way that small children do (look at all the people in the mall, mommy, there must be a million of them!). There are some battles where their claims of the number slain in a day were over a billion, cut down by intrepid thousands. Historians have to sift through that kind of thing.