I guess it stands to reason that buildings full of dried papyrus might fall victim to more than one fire over the centuries.
From CAESAR AND CLEOPATRA (1945)
THEODOTUS (on the steps, with uplifted arms). Horror unspeakable!
Woe, alas! Help!
RUFIO. What now?
CAESAR (frowning). Who is slain?
THEODOTUS. Slain! Oh, worse than the death of ten thousand men!
Loss irreparable to mankind!
RUFIO. What has happened, man?
THEODOTUS (rushing down the hall between them). The fire has
spread from your ships. The first of the seven wonders of the world perishes. The library of Alexandria is in flames.
RUFIO. Psha! (Quite relieved, he goes up to the loggia and
watches the preparations of the troops on the beach.)
CAESAR. Is that all?