Answer:
1. Wars and battles between Christians and Muslims. The rise of Islam and its religion caused many changes because it was another religion followed by many people in a large area, in an short amount of time. Because Islam was rising this caused a war with the Christians.
2. Plague spreading across Europe. The Black Death spread very quickly throughout Europe killing many people. Because so many people were dying and trying to stay home so that them and their family would be safe, the economy wasn't able to grow. Because of this the economy went down.
3. Trade. The Ottoman Empire affected trade since a lot of its territory was part of the Silk Road and they wouldn’t let travelers through which led to more trade routes to be made and or discovered.
Step-by-step explanation: