The effects of the Crusades tended to favor the Christian world of Western Europe when compared to the Muslim world of the Middle East. The Crusades began the breakdown of feudal society in Western Europe. Many feudal lords went off to fight and die in the Crusades, leaving their serfs free to go to towns and start new lives. Monarchs gained new strength when knights left to fight in the crusades in the Middle East. This increase in the power of the monarch also helped to end feudalism. Crusaders brought back goods such as spices and cloth, which increased demand for these goods. Merchants, particularly in Italy, grew rich from this new trade with the East. Crusaders also brought back Greek and Roman classical works. The wealth from trade and new knowledge of classical Greek and Roman works sparked the Renaissance in Europe.
Muslims did not fare as well. Most fighting took place on Muslim territory so many Muslims lost their lives and much property was destroyed. Muslim society was more advanced than European Christian society, so knowledge flowed from east to west. Some Muslim merchants did become wealthy from trade with Europe, enabling the funding of projects such as new mosques and religious schools.