The effects of the Crusades are widely debated. Some scholars would argue that the Crusades did a number of things. Among them, the Crusades
- Broadened the horizons of European civilization. They did this by exposing Europeans to the Muslim world and the knowledge that Muslims had preserved from classical times.
- Stabilized European society. They did this by taking a large number of young warriors out of Europe. Instead of fighting one another in Europe, they went and fought in the Middle East.
- Helped to make Italian port cities richer. Places like Genoa, Pisa, and Venice became richer by supplying the Crusades and through the trade that came after the Crusades.
Some of these are debated among scholars and you will want to consult your text to make sure that your answer agrees with the interpretation given by the authors.
It is also important to note that the Crusades had at least one very negative effect within Europe. This was the first time that large-scale massacres of Jews occurred in Europe. Crusaders conducted a number of attacks on Jews since Jews were (like Muslims) non-believers in Christianity.
People stopped Crusading because they realized that God didn't like how they killed each other.