You learned about the crusades in school. You learned about those evil bigoted European Christians spreading their religion with violence, waging war in the name of God. You didn't hear about the rampaging hordes of Muslims on a jihad to spread Islam by the sword. You didn't hear much about the eastern Roman Empire and Constantinople, and how it was invaded and occupied by Muslim jihadis, and all of this happened around the same time that the crusades started - the crusades to liberate the stolen land from the foreign invaders. You heard about European Christians traveling to Jerusalem. You didn't hear much about the Muslims invading Jerusalem, which had been a Christian territory for hundreds of years as part of the eastern Roman Empire, which was a Christian nation after 300 A.D. And I sure as hell never heard of Al-Andalus. Did you know that Muslims invaded Spain and occupied it for hundreds of years before the land was liberated from the invaders? Catholic Spain was a Muslim caliphate! Didn't learn that in school!