1066, the Norman Conquest of England

England...'was a farming country, land was its absorbing interest; and
originally plots of land had been owned outright by the men who settled and
cleared them, and inherited by their children. But such independent farmers
had no defense against the Viking raids, or resources to tide them over disasters
like cattle sickness, a series of bad harvests, fire or storm. In the course of time,
almost every man in the country had attached himself by mutual promises to
somebody more powerful, who could help to protect him and his family in times
of stress. …