What were the social, economic, and political effects of the Crusades?

The Crusades had a major effect on commerce, as the crusaders often brought goods, such as silks, perfumes, ivory, pearls, and spices, across the Mediterranean to the ports of Italy. This trade stimulated a demand for eastern goods into Europe, and trade with the East became increasingly important. In addition, the Crusades created an immense demand for ships to transport the crusaders to the East. Italian cities such as Genoa and Venice became wealthy through trade to the East. Politically, the Crusades resulted in the weakening of feudalism and the growth in royal power. Many of the knights who were important in propping up feudalism went on the Crusades. Their absences or death resulted in the collapse of many estates, which were then transferred to kings. The Crusades also resulted in the intellectual and social advancement of Europe, as knights returned with knowledge of science and literature that was far more advanced in the East than in Europe at the time. As a result, the Middle Ages eventually gave way to a rebirth in learning and exploration known as the Renaissance.