Were the Crusades Political or Religious?

The Middle Ages was a religious age that was dominated by papacy. The Crusades show the religiousness of the Europeans in the Middle Ages, though we question ourselves if that was their only motive: Religion. People fought the Muslims, Seljuk Turks, to regain the Middle East in the name of "crusaders" which means "marked with the cross". This was the beginning of the Europe's waking up to use their growing power to look outside Europe and dominate more lands for religious, economic and political reasons. As many as 600,000 crusaders left Europe and marched overland to Jerusalem to "save" the Holy Land of Christianity despite its many difficulties and danger facing them. So then why would all these many crusaders have left their home, family behind to face the threat of the diseases and most likely death? Would it really only have been the pure faiths of religion in them? Or was there something else beyond religious aspects that the Christians wanted? Were the Crusades political or religious?…