I thought it was somebody else, but it's of no matter.
Had the Romans (and others) not burned the library at Alexandria (several times), we'd know a hell of a lot more about what the world knew and didn't know before Mohammed showed up.
I'd vote for that as possibly the single greatest crime in the history of the world. A tremendous setback. It's completely imponderable what things had to be re-discovered perhaps centuries later. Perhaps some things that haven't yet been re-discovered. Who knows?
I suppose that it's likely a moot point. If it hadn't already been burned, Mohammed might likely have been the one to do it anyway. :-)