Ineed > i dont have lots of time for this. will mark as five to ten sentences explain how the feudal system worked

Feudalism was a popular societal structure in Europe during the Middle Ages (between the 9th and 15th centuries), which arose in response to the state of chaos which had befallen Western Europe for centuries after the fall of the Western Roman Empire in 476 C.E. In fear of raids on the lower class (which made up the majority of the European population at the time), the feudal system, a system of land ownership and duties, was developed. Based on the exchange of land for military service, it demanded that everyone owed allegiance to the king and their superiors. In other words, the nobles pledged their support to their king both financially and militarily in exchange for land 
and prestige. In turn, the nobles ensured their lands would be protected by promising knights (vassals), small portions of their land in exchange for fealty. This phenomenon was known as "fief" and was a big part of feudalism. Finally, the knights and vassals would allow peasants (serfs) to live on their lands in exchange for food and other services, thus completing what is often known as the feudal pyramid.