Feudalism already partly existed in England when the Normans arrived at the beginning of the 11th century. The Normans only developed it and made it more robust. The land was owned by the King and held by the Vassals which were giving military and other services, as well as goods, in the return. The Barons were the chief vassals and they could nominate other vassals, the Knights and the Villains, who would serve their purposes.
The agricultural land was divided following the “manorial system”. The lord, or baron, lived in the Manor (as it was called in the Domesday Book introduced by King William I the Conqueror), he kept some arable land (his “demesne”) and held the rights over the hunting and fishing grounds. The rest of the arable land he gave to the peasants, open fields were used as pastures and the other lands, such as meadows, were communal.
The peasants were villains or servants; the difference was that the villains were free but linked to the land where they were born as this passed through the families, from father to son. The peasants gave services to their lord in the form of labor, while the knights gave it in the form of military service.