The document discusses the feudal system in Britain. It explains that the feudal system was a hierarchy where the King granted land to barons in exchange for their loyalty and military service. The barons then granted land to knights who promised to serve and fight for their baron. Knights granted land to peasants who worked the land in exchange for protection. The feudal system allowed William the Conqueror to control the country after his invasion of England in 1066 by rewarding his supporters with land and positions of power in the new system.