The Crusades were a series of military expeditions during the Middle Ages, and while there were many motivations and outcomes of the Crusades, here are some points that explain the role of defense against Muslim attacks ¹ ² ³:
· The Crusades were also seen as a way to check the spread of Islam.
· Approximately two-thirds of the ancient Christian world had been conquered by Muslims by the end of the 11th century.
· The Crusades were a defensive war in response to hundreds of years of Islamic expansion and aggression against Christian peoples which was now threatening to overwhelm Europe.
· Islamic armies, starting with their Prophet Mohammed himself, had already conquered and subjugated two thirds of the Christian world including the Holy Land, Egypt, North Africa, and Spain.
· The Byzantine Emperor Alexius requested aid from Pope Urban II in response to the expansionist intentions of the Muslim world.