The crusades brought big changes for Europe. The political system in Europe changed from feudalism to monarchy. The economic system went from the manorial system, where manors were self-sufficient and didn't trade, to the revival of trade throughout Europe. The social structure went from a structured society to a society with a new class, the middle class, and the decline of serfdom. All these changes were very big for Europe.

The political system changed in a big way in Europe after the crusades. Before the crusades, the political unit was the manor and was ruled by lords. You were loyal to the lord who owned your land. After the crusades, feudalism became weaker. The kings who led the crusades got more power. They began to form countries and impose taxes. People gave their loyalty to kings in exchange for protection. As long as the king promised to keep...