The Middle East and the Middle East Crusades

The climate in europe had gradually been warming from about the eight hundreds through the one thousand. Productivity of farms was massively increasing. Much bigger and more reliable food surpluses were available. Towns and cities were growing, and there was now much more a mobile population around. So that made a sort of mass movements and concerted action much more conceivable than it would have been 100 or 200 years earlier. Another is geo political. It's the ongoing a conflict between islam and christianity.