Which group fought with each other in the crusades Why were they fighting?

The Crusades primarily involved European Christians and Muslim groups, particularly the Seljuk Turks and later the Ayyubids, among others. They fought over control of the Holy Land, especially Jerusalem, which held significant religious importance for both Christians and Muslims. The Crusaders aimed to reclaim territories that had been conquered by Muslims, while Muslim forces sought to defend their lands and faith from foreign invaders. This conflict was fueled by religious fervor, territorial ambitions, and the desire for economic gain.