<P> The Library of Alexandria was one of the largest and most significant libraries of the ancient world . Famous for having been burned, thus resulting in the loss of many scrolls and books, it has become a symbol of "knowledge and culture destroyed". Although there is a traditional account of the burning of the Library at Alexandria, the library may have suffered several fires or acts of destruction, of varying degrees, over many years . Different cultures may have blamed each other throughout history, or distanced their ancestors from responsibility, and therefore leaving conflicting and inconclusive fragments from ancient sources on the exact details of the destruction . There is little consensus on when books in the actual library were destroyed . Manuscripts were probably burned in stages over eight centuries . </P> <P> Ancient and modern sources identify four possible occasions for the partial or complete destruction of the Library of Alexandria: Julius Caesar's fire during his civil war in 48 BC; the attack of Aurelian in AD 270--275; the decree of Coptic Christian pope Theophilus of Alexandria in AD 391; and the Muslim conquest of Egypt in (or after) AD 642 . </P> <P> The ancient accounts by Plutarch, Aulus Gellius, Ammianus Marcellinus, and Orosius indicate that troops of Caesar accidentally burned the library down during or after the Siege of Alexandria in 48 BC . </P> <P> Plutarch's Parallel Lives, written at the end of the 1st or beginning of the 2nd century AD, describes the Siege of Alexandria in which Caesar was forced to burn his own ships: </P>

When did the library of alexandria burn down