According to the Dictionary, feudalism is “the dominant social system in medieval Europe, in which the nobility held lands from the Crown in exchange for military service, and vassals were in turn tenants of the nobles, while the peasants (villeins or serfs) were obliged to live on their lord’s land and give him homage, labor, and a share of the produce, notionally in exchange for military protection.” So in summary it means that people were allowed to live on the lord’s lands and supply him with work and other things. What’s in it for the people living on the land? Military protection. Why would they need military protection? Because this was during the times of Barbarian and Viking invasions.
According to Britannica, “manorialism, also called manorial system, seignorialism, or seignorial system, political, economic, and social system by which the peasants of medieval Europe were rendered dependent on their land and on their lord.” So, it was the method of land ownership at this time.