"Thus it is accepted myth that during the Crusades an expansionist, imperialistic Christendom brutalized, looted, and colonized a tolerant and peaceful Islam. These claims have been utterly refuted by a group of distinguished contemporary historians. They propose that the Crusades were precipitated by Islamic provocations, by many centuries of bloody attempts to colonize the West, and by sudden new attacks on Christian pilgrims and holy places." - Stark TC, p216.
Who is your history teacher? What are his faith-assumptions? Where did he study? What were their faith-assumptions?
Stark notes that by the time of the First Crusade, Christendom had been fighting a defensive war with Islam for more than 450 years (p217). After dispelling many myths of various heinous crimes of the Crusaders, Stark concludes:
"The Crusades were not unprovoked. They were not the first round of European colonialism. thew were not conducted for land, loot, or converts. The crusaders were not barbarians who victimized the cultivated Muslims. The Crusades are not a blot on the history of Christianity. No apologies are required." - p234.
It was a very provocative chapter and worth reading in its entirety.