If these writings of the Greeks agree with the book of God, they are useless and need not be preserved; if they disagree, they are pernicious and ought to be destroyed.

Umar I (c. 583-644) Arab caliph, jurist [Omar, Umar ibn Al-Khattāb, Al-Farooq]

(Attributed)

Ordering the burning of the Library of Alexandria in AD 641, as quoted in Edward Gibbon, The Decline and Fall of the Roman Empire (1776-88). The story is generally considered spurious. More discussion here. Alt. trans.: "They will either contradict the Koran, in which case they are heresy, or they will agree with it, so they are superfluous"