The Feudal System
Feudalism emerged in response to the need for governments to be able to protect their subjects. The system worked because lower classes agreed to serve upper classes in exchange for protection. When the system ran smoothly, it led to peace and prosperity for everyone. Above all, the king relied on the system to enable him to run the kingdom smoothly.
At the top of the feudal system was the king. He presided over the land that he ruled, directing and controlling what happened in his kingdom. In kingdoms so vast, the kings relied on nobility and knights to help manage their subjects.
The king would divide his kingdom among the nobility, who were the richest and most powerful families in the realm. Each noble operated a particular portion of the kingdom, overseeing and governing it.
In exchange for their power, the nobles pledged their loyalty to the king. Part of that loyalty meant a willingness to raise a local army should their king call for it. During the Middle Ages, armies were localized, and ordinary men took up arms at the command of their local nobility.
Knights and Vassals
Even the land of the nobility was divided up into smaller parcels run by knights or vassals. Both of these groups traded military support for land in the local manors.
As higher-ranking people, knights often presided over an entire manor, while vassals presided only over the land needed to support their families.
In both cases, the knights and vassals had command over the serfs that worked the land. In exchange for this control, they promised to fight in defense of the lord and the king if needed.
By far, the largest portion of the population of the people in the Middle Ages were the serfs. Some serfs, such as cobblers, bakers, coopers, or blacksmiths, had relative freedom and even owned their own homes or businesses.
Most serfs, however, lived a very hard life that was not that much different than slavery. They were tied to the land they worked and were not allowed to own anything. Most barely made enough to survive and often suffered of hunger.