A Catholic clergyman named Martin Luther (1483–1546) had initiated history’s Protestant Reformation. Whatever else can be said of him, Luther unwittingly did much to weaken European unity against invading Islam. Although he maintained the traditional Christian view on Islam—denouncing the Koran as a “cursed, shameful, desperate” book filled with “dreadful abominations”—he condemned the concept of crusading and originally preached passivity45 against the Muslim invaders,*
