Was the Library of Alexandria destroyed in a single fire?
No. The image of a single catastrophic night in which ancient knowledge was lost is a much later construction — the library declined over centuries through funding cuts, political neglect and the gradual dispersal of scholars, which is a far less dramatic and far more instructive story.
What the library was. Part of the Mouseion, a research institution founded in the third century BCE under the Ptolemies, with state-funded scholars, a dining hall and — genuinely remarkable — an ambition to collect a copy of every book in existence. Ships entering Alexandria reportedly had their scrolls seized, copied and the copy returned.
The candidate destructions, all partial and several doubtful:
Julius Caesar's fire of 48 BCE, where fire spread from ships in the harbour and destroyed warehouses containing scrolls. Sources disagree about how much, and the library clearly continued to function afterwards.
Aurelian's campaign in the 270s CE, which devastated the royal quarter where the library stood.
The destruction of the Serapeum in 391 CE, a daughter library, in a period of religious conflict.
The Arab conquest of 642 CE, a story that appears six centuries after the event and is regarded by most historians as a later invention.
What actually destroyed it. The most persuasive explanation is institutional decay. Royal patronage was withdrawn, scholars were expelled during political purges, funding declined under Roman administration, and Alexandria lost its status as the Mediterranean's intellectual centre. Papyrus also degrades, so a collection requires continuous recopying — and when nobody is paid to copy, a library dies quietly.
Why the myth persists. A single villain and a single night make a better story than budget cuts across three hundred years, and the image has been deployed repeatedly as a warning about barbarism destroying civilisation.
What was genuinely lost. A great deal, though not all of it uniquely — many texts existed elsewhere, and the majority of classical literature was lost through failure to recopy across late antiquity and the medieval period rather than through any fire.