'91 appears to have been an important anniversary year that we all missed....
But, March is a month completely without interesting holidays.... So, how about the Ides of March?....
http://www.greece.org/alexandria/library/library1.htm
-- The persistent question that is invariably asked when mention is made of the Alexandria Library, is how the greatest collection of books in the ancient world came to an end. To cut a long story short, we know that there were two principle centres wherein the books were kept: the Royal Library, located close to the harbour within the precincts of the royal palaces, and the Daughter Library, incorporated in the Sarapeum, south of the city. The Royal Library The Royal Library was an unfortunate casualty of war. In 48 BC., Caesar found himself involved in a civil war between Cleopatra and her brother Ptolemy XIII. Caesar sided with Cleopatra and was soon besieged by land and sea by the Ptolomaic forces. He realised that his only chance lay in setting fire to the enemy fleet and it was by this drastic measure that he managed to gain the upper hand. But the fire, in the words of Plutarch, spread from the dockyards and destroyed the "Great Library" (megalé bibliotheke) [ Caes. 49]. The Daughter Library As regards the Daughter Library, it continued to function throughout the Roman period under the protection of the Sarapeum. Nevertheless, with the end of paganism and the ascendancy of Christianity in the fourth century, the Sarapeum lost its sanctity. In 391, when the Emperor Theodisius ordained the destruction of all pagan temples, contemporary eyewitnesses assert that the Sarapeum, together with all its contents, suffered complete annihilation. [Rufinus, H.E. 2. 23-30; Eunapius, vit. Aedesii, 77-8; Socrates, H.E. 5.16.]. The Arab Conquest Thus, when the Arabs conquered Egypt in 642, the Alexandria Library no longer existed. It is noteworthy that no historians of the conquest, whether Byzantine or Arab, ever mention any accident that could have occurred to the Library. It was not until six centuries later, during the time of the Crusades, when all of a sudden a story emerges, claiming that the Arab general Amr Ibn Al-As, had destroyed the books by using them as fuel for the baths! [Ibn Al-Quifti 354]. Modern scholarship has proved beyond any doubt that this story was a twelfth century fabrication, resulting from war conditions during the Crusades. [For a full treatment of the subject, cf. A.J. Butler, The Arab Conquest of Egypt, 400 ff.; M. El-Abbadi, Life and Fate of the Ancient Library of Alexandria, 136-166].