Crusades (almost) Entirely Supported 

Throughout Holy Roman Empire

These "soldiers of the Church" took vows to take back the Holy Land

The Pope promised those who died in the endeavor would receive immediate remission   for their sins

Roger Bacon warned 'em: "(Muslims) who survive, together with their children, are more and more embittered against the Christian faith."(...but few listened to him)

So, how did it go?  Who won?

1st Crusade (1095-1099): Christians take Jerusalem; Muslims take it back in 1144

2nd Crusade (1147-1149): Muslims keep Jerusalem, but Christians take Lisbon, Portugal 

3rd Crusade (1187-1192): Richard the Lionheart and Saladin work a deal: Muslims control Jerusalem, but Christians can worship there

4th Crusade (1202-1204): Crusaders get distracted and sack Constantinople, creating a huge rift between the eastern (Byzantine) Church and the western (Catholic) Church; then there's the Children's Crusade - a horrible idea, if it actually occurred

5th Crusade (1217-1221): Muslims beat Christians in Egypt 

6th Crusade (1228-1229): Christians take Jerusalem, let Muslims have Dome of the Rock; Muslims take it back in 1244 

7th Crusade (1248-1254): Muslims fight off Christians

8th Crusade (1270):  no resolution 

9th Crusade (1271-1272):  any remaining Franks in the Middle East are either massacred or enslaved