…The world’s largest and oldest library was in Alexandria, Egypt. Accounts were given by Persian traveler Abd-Al-Latif of Baghdad (1162-1231), Jamal Ad-din Al-Kufti (1169-1248), and Syrian prelate Bar Hebraeus (1226-1286) that when Caliph Omar was asked in 642 AD what to do with the books in the library, he told his commander Amr bin al-Ass: “Touching the books you mention, if what is written in them agrees with the Qur’an, they are not required; if it disagrees, they are not desired. Destroy them therefore.”
The account continued that the library books were burned to heat the city’s bath-houses for six months. Other libraries in Babylon, Syria and Greece met similar fates.