What destroyed the Library at Alexandria, Egypt?
There are three accepted possibilities: Julius Caesar setting the piers afire, Christian extremists ( See recent film Agora as example) and Muslim conquest and resulting extremists. I believe that it was the development of the codex in the First Century C.E. The drive to amass the library and to copy all the scrolls of every ship that docked at Alexandria dissipated. But the scrolls, supposedly 750,000 of them, were still extant. Many of the existing scrolls were not copied and transferred to codex form and were scattered and destroyed by the events of history.