Quote from : Assassin's Creed: The Secret Crusade Book

They do not learn, fixed in their ways as they are. You are naïve to think otherwise. It’s an illness, Assassin, for which there is but one cure.’ ‘You’re wrong. And that’s why you must be put to rest.’ ‘Am I not unlike those precious books you seek to save? A source of knowledge with which you disagree? Yet you’re rather quick to steal my life.’ ‘A small sacrifice to save many. It is necessary.