After the first crusade of 1095, the Pope made a proposal. ‘Whoever for devotion alone, but not to gain honor or money, goes to Jerusalem to liberate the Church of God, can substitute this journey for all penance.’ The Christians were trying to push the Muslim invaders from Sicily and around. Every church rewarded the fighters.
Pope Urban was trying to protect his people against exploitation of the weak. The recovery of the holy city of Jerusalem from Islam was rewarded with sins forgiven. As the papacy was engaged in a power struggle with the German emperor, Henry IV, the Crusaders took advantage. The Crusaders got a helping hand from the Byzantine Empire too. Pope Urban took advantage of the crusade to patch to the Orthodox and to heal the rift.
The impact of the Crusades was in the field of military, religious, and culture in Europe and the Middle East. For the last four decades, the Crusades persuaded people in the Christian West to recapture Jerusalem. The impact was from the Muslim, Christian and Jewish communities of the eastern Mediterranean. The scope of the Crusades widened beyond the original 11th-century expeditions to the Holy Land. They took place long after the end of the Frankish hold on the East (1291) and continued down to the 16th century.
Incidentally, Crusades were also called against the Muslims, the Mongols and the political opponents of the Papacy. The Crusaders gave heartfelt thanks for their success as they reached their goal, the tomb of Christ in the Holy Sepulchre. Crusading resulted in the conquest of the Iberian Peninsula (now Spain and Portugal), and the curtain fell finally completed in 1492 when the Spanish monarchs Ferdinand II and Isabella I conquered the last Muslim community on the peninsula—the city of Granada. It goes without saying that the Crusades also had a highly adverse effect on interfaith relations. When the Ottoman Empire was in crisis, the crusades went down along with the church.
Reference URL: ttps://www.khanacademy.org/humanities/world-history/medieval-times/the-crusades-technology-and-culture/a/the-impact-of-the-crusades-4-of-4