The Great Library of Alexandria was one of the Wonders of the Ancient World.
Its destruction by fire, begun by accident in 48 BC by the Roman general Julius Caesar when tactics forced him to set fire to his own fleet, moored in the harbour of Alexandria, and the blaze spread first to the docks and then to the Library itself, and completed by the Caliph Omar – he who entered Jerusalem on a white camel – nearly seven centuries later in 642 AD, (during the first frenzied and seemingly irresistible flames of the Islamic Faith rampaged through the Arab world), was a severe setback for Western Civilization.
The Library had contained about seven thousand scrolls written by Greek, Persian and Egyptian poets, writers and philosophers.
The Caliph Omar is said to have commented: If they are to be found in the Koran then they are not needed. If they are not to be found in the Koran then they are harmful.
How much of the fruit of that wise age was lost?
Not all of the most powerful search-engines in the world can discover that because it became unknown or non-knowledge.