What are some factors that motivated Europeans to participate in the crusades?

The major forces that motivated the Europeans to participate in the crusades were religious, economic, and political. Many were motivated by a religious belief that they should fight to protect and be in control of the Christian holy lands to prevent Muslim control and domination. In addition there were economic and political gains that could be made through control of the Holy Land. There was also an element of prestige that was sought in how European civilization would be regarded if it could control the Holy Land.