the feudal system of medieval Europe

Feudalism was the relationship between the lord and his vassal.
Feudalism society order went like this.
Kings and Queens were the greatest lords of Europe , and all knights were their vassals.
Next were the nobles, nobles were also kings and queens. Many were also lords of lower ranking nobles and knights.
Next were the knights, the knights served their noble lords in exchange for land instead of money.
Last but not least because they get the food for the entire community, were the peasants, the peasants owned no land, so they were not part of the feudal system. but many peasants worked on land owned by nobles or knights. Because they worked for the lords or knights on their land they were called serfs.
Knights were warriors who fought on horse back. They served other knights and vassals.
Vassals were just knights with a little more power because they promise to support the king in exchange for land.
the peasants (or serfs) lived on a manor which was run by a lord or a knight. The serfs were tied to that land until either their lord or knight died, or he set them free.