Let's start by saying that initially the Crusades were not a "holy war" on the part of Europeans against Islam, but in important ways the Crusades were driven by religious faith.
Mr. Green, Mr. Green! Religion causes all wars. Imagine no war… I'm gonna cut you off right there before you violate copyright, me-from-the-past. But as usual, you're wrong.
Simple readings of history are rarely sufficient. By the way, when did my handwriting get so much better?
I mean, if the Crusades had been brought on by the lightning-fast rise of the Islamic empire and a desire to keep in Christian hands the land of Jesus, then the Crusades would've started in the 8th century.
But early Islamic dynasties, like the Umayyads and the Abbasids, were perfectly happy with Christians and Jews living among them, as long as they paid a tax.
And plus the Christian pilgrimage business was awesome for the Islamic Empire's economy.
But then a new group of Muslims, the Seljuk Turks, moved into the region and they sacked the holy cities and made it much more difficult for Christians to make their pilgrimages.
And while they quickly realized their mistake, it was already too late.
The Byzantines, who'd had their literal-asses kicked at the Battle of Manzikert in 1071, felt the threat and called upon the West for help.
So the first official crusade began with a call to arms from Pope Urban II in 1095 CE.
