The Bubonic plague
The bubonic plague played a huge roll in Medieval Europe. The word plague means an infectious disease that causes a high death rate. The plague killed nearly one fourth of the population of Europe. The plague is carried by rodents and transfered to humans by fleas. The plague started because for many reasons. Mainly, the plague started because of the cramped living space. There was very little room in cities for people to live in which allowed the plague to spread quickly.
The Feudal System
The Feudal System was a very effective way of government for a very large part of Medieval Europe. That was how the government was run: Feudalism. Feudalism was the exchange of service for land. There were four classes of feudalism in Medieval Europe: The Kings, the Nobles a.k.a lords, the knights and the freemen/serfs. The serfs gave the nobles labor in exchange for a home and food. The knights gave the nobles protection and loyalty in exchange for land and food as well, and the nobles gave the king loyalty in exchange for land. The land that a noble owned was called a manor. Each manor had it's own knights and serfs and one noble. The manor was usually a big area that was near the castle.
The Crusades
The Crusades were a big part of Medieval Europe. Three major religions tried to claim Jerusalem as their Holy City. Those religious groups were the Jews, the Muslims and Christians. People fought because it was a chance to get richer, to have the ability to instantly get into heaven, and to escape their boring and labor-filled lives. The Feudal System was very bad for feudalism. Since feudalism depended on all the social classes to participate, and the knights and most of the serfs were gone, there was no one to do the labor and to protect the manor. The symbol of the crusades is the red cross.