Burning Egypt Alexandria Library 48 B.C. is Post 509 B.C. coup of Roman King.

Prior destruction by Erope, 509 B.C. coup  in Rome.

The first person blamed for the destruction of the Library is none other than Julius Caesar himself. In 48 BC., Caesar was pursuing Pompey into Egypt when he was suddenly cut off by an Egyptian fleet at Alexandria. Greatly outnumbered and in enemy territory, Caesar ordered the ships in the harbor to be set on fire. The fire spread and destroyed the Egyptian fleet. Unfortunately, it also burned down part of the city - the area where the great Library stood. Caesar wrote of starting the fire in the harbor but neglected to mention the burning of the Library. Such an omission proves little since he was not in the habit of including unflattering facts while writing his own history. But Caesar was not without public detractors. If he was solely to blame for the disappearance of the Library it is very likely significant documentation on the affair would exist today.

The second story of the Library's destruction is more popular, thanks primarily to Edward Gibbon's "The Decline and Fall of the Roman Empire". But the story is also a tad more complex. Theophilus was Patriarch of Alexandria from 385 to 412 AD. During his reign the Temple of Serapis was converted into a Christian Church (probably around 391 AD) and it is likely that many documents were destroyed then. The Temple of Serapis was estimated to hold about ten percent of the overall Library of Alexandria's holdings. After his death, his nephew Cyril became Patriarch. Shortly after that, riots broke out when Hierax, a Christian monk, was publicly killed by order of Orestes the city Prefect. Orestes was said to be under the influence of Hypatia, a female philosopher and daughter of the "last member of the Library of Alexandria". Although it should be noted that some count Hypatia herself as the last Head Librarian.