Answer:
your answer is they fought because they were motivated by God!
Step-by-step explanation:
he purpose of all these crusades was ostensibly twofold. Popes authorised warfare in Christ’s name because they thought it was their duty to protect Christian people and lands from non-believers. Ordinary medieval people took crusade vows, sewed distinctive cloth crosses to their garments and joined crusader armies because they were promised that in doing so they would earn forgiveness for their earthly sins, thereby easing their passage into heaven.
These two aims were repeated throughout the history of crusading. When Urban II launched the First Crusade, chroniclers recalled that he spoke of avenging insults to (“the sanctuary of God”) by declaring “wars which contain the glorious reward of martyrdom”. The great Cistercian abbot Bernard of Clairvaux helped preach the Second Crusade, which began in 1147, calling upon the knights of western Europe to join “a battle [where] you may fight without danger, where it is glory to conquer and gain to die”. When Pope Gregory VIII preached the Third Crusade in 1187, after Jerusalem had fallen to the sultan Saladin, he asked crusaders to be “courageous, because it is better to perish in a fight than to behold the profanation of holy things”.