The Crusades
“The Crusades were not unprovoked; they were a response to more than four centuries of conquests in which Muslims had already captured two-thirds of the old Christian world. At some point, Christianity as a faith and a culture had to defend itself or be subsumed.”
— Rodney Stark, a Protestant sociologist and historian
Source: Stark, Rodney. God’s Battalions: The Case for the Crusades. HarperOne, 2009.