What were the crusades? and how did they serve to weaken the byzantine empire.

The crusades were holy wars in the middle east, they weakened the Byzantine empire through the sacking of Constantinople by Crusaders.  It also led to the Ottoman's surrounding the city of Constantinople and laying siege through the use of cannons, thus ending Byzantine and the rise of Istanbul.

Explanation:

Global contact create social and cultural change during the Renaissance because with the global contact, ideas were transferred from one region to another which change the culture and social behaviour of the society. The European societies changes due to the fall of feudalism and the rise of a capitalist market economy in the European countries during Renaissance. These ideas were taken from other cultures when they globally contact with each other.