Why did the crusades contribute to the end of the medieval era in europe?

The answer has been stated below.

Explanation:

Crusades were the war in the name religion. while creating an army for the crusades, kings began to imply taxes on the nobility and nobility had to sell off their lands and freed their serf. The central authority of the King become strong by leaving taxes on the eastern trade. The new nation-states broke the old feudal ties.