The Crusades

Yesterday I watched the movie, Kingdom of Heaven. It's a movie about the medieval crusades that I know I need to do much research on. But the whole movie (though I did fall asleep for about a half hour) seemed to have an over-arching sadness to it. What possessed these people to kill, slaughter and rape those who did not share the same beliefs as them? And throughout the movie those in authority kept saying over and over, "It is God's will for us to do such and such." Usually that such and such was killing, slaughtering or even initiating a war. What? God's will? How do you know? Are you coming before God in prayer, meditating on His word day and night and begging for peace and salvation for all? They were so misguided. It makes me so mad and so sad that Christians and Muslim's today have this huge gap between them because of these foolish crusades that happened hundreds and hundreds of years ago.