Alexandrian library

The Royal Library of Alexandria in Alexandria, Egypt, was once the largest library in the world.It is generally thought to have been founded at the beginning of the 3rd century BC, during the reign of Ptolemy II of Egypt. The Library was likely created after his father had built what would become the first part of the Library complex, the temple of the Muses — the  Museion, Greek Μουσείον (from which the modern English word museum is derived).
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Alexandrian Library Begun by Ptolemy Soter (367?-283 BC), and zealously pursued by his successor Ptolemy Philadelphus. The two principal libraries were in the Bruchium and the Serapeum; the number of rolls or "books" is variously estimated between 400,000 and 700,000, but these rolls had not the contents of a modern printed volume. The Bruchium was accidentally set on fire when Caesar burnt the fleet in the harbor, but many rolls were rescued. The Bruchium quarter was destroyed by Aurelian in 273 and probably the library with it; and in about 390 Theodosius ordered the destruction of the Serapeum, and its books were pillaged by Christians. The Moslem Caliph `Omar is reputed finally to have destroyed the remainder of the library.