The concept of a landlord may be traced back to the feudal system of manoralism (seignorialism), where a landed estate is owned by a Lord of the Manor (mesne lords), usually members of the lower nobility which came to form the rank of knights in the high medieval period, holding their fief via subinfeudation, but in some cases the land may also be directly subject to a member of higher nobility, as in the royal domain directly owned by a king, or in the Holy Roman Empire imperial villages directly subject to the emperor.