On the positive side:
- The Crusades led to the development of trade and cultural exchange between Europe and the Middle East.
- They helped to strengthen the power of the Catholic Church.
- They led to the development of new technologies, such as the crossbow and the castle.
- They also led to the development of a more centralized European state system.
On the negative side:
- The Crusades were often violent and bloody, and they resulted in the deaths of millions of people.
- They also led to the persecution of Jews and Muslims in Europe.
- The Crusades also led to the rise of religious extremism and intolerance.
- They also contributed to the decline of the Byzantine Empire.