What motivated people to volunteer for the crusades?

What engineering feat connected all parts of the Roman Empire? Where does the term Nords come from? What is the origin of the name Brigitte? What Was the only country in the 19th century Western Hemisphere that allowed slavery? What were the roots of the Cold War? What internal and external struggles occurred during the rise of the roman republic? How do you write 850 in roman numbers? Who of the following historians has organized her study of the past based on the category theme? How could the Lewis and Clark expedition prepare people who wanted to move west? Charlemagne began the line of kings known as the? Compare the roman empire and the british empire? Why did European overseas empires crumble after World War 2? Why did European nations want to expand? What time period did Kublai khan live in? Did Charlemagne find the Carolingian Empire? What problems did Rome face in attempting to rule the vast territory from Spain to Asia minor? What money did medieval people use in England? What were the unintentional consequences of the crusades? Who was a famous roman astronomer? Who were the main inspirations for European exploration?

What motivated people to volunteer for the crusades?