1. The Objective of the crusades was to recapture the fallen major cities of Christendom that had been taken by the Muslims centuries before.
2. The two major factions were attacking European-Catholic Crusaders and defending Middle-Eastern Muslim nations.
3. Most of the fighting took place in the Levant, or for a more general region the Middle East as a whole.
4. The most successful crusade was the first that occurred from 1096 - 1099, and resulted in several Crusader states being established on the eastern Mediterranean coast.
