The crusades were a series of military expeditions carried out by Christians from all throughout Europe during the Middle Ages. The crusaders travelled to the Middle East in an attempt to seize the Holy Land from the Muslims who lived there and controlled the region. Although considered to be a violent and unfortunate event in Christian history, the crusades played a significant part in the rise of the Renaissance in Europe.

The crusades led to the first interactions between the West and the cultures of Palestine, Greece, and Asia Minor. In these regions, scholars still circulated classical tomes such as the Aristotelian texts, which had long been lost to the Western world. Europe was therefore able to rediscover Greek philosophy and gain new knowledge of mathematics, logic, and scientific thinking—some of which contradicted the doctrine of the Catholic Church. This new knowledge was central to the Renaissance movement.

The second way that the crusades led to the Renaissance was through their mass pilgrimages. Because a significant percentage of the European population had left their homes and journeyed to the Holy Land, new trade routes were created to feed, clothe, and arm these crusaders. Some port cities in Italy, in fact, grew to such wealth and prominence during this time that they became renowned city-states of the Renaissance. Additionally, the mass pilgrimages also weakened the European feudal system—and by extension, the absolute monarchy. Apart from the abandonment of local fiefs, the increase in trade also led to the formation of a new middle class. This led to the collapse of feudalism, the monarchy, and the subsequent formation of a Renaissance ideal: the city-state.