Feudalism, a word coined in the 17th centry, is generally used to describe a social structure in which an aristocratic warrior class dominates a large peasantry and is sustained by its labour. More precisely, it refers to the social organization of the Middle Ages in which relationships between members of the aristocracy -- and especially between the king and the dukes or counts -- were based on lordship and vassalage.

The vassal, the inferior partner, received his fief -- usually a parcel of land -- and protection from the lord. In return he did service, either by taking a contingent of knights and other troops to fight in his lord's army, or by paying his lord money for the hire of mercenary soldiers. The fief was conferred by the ceremony of homage: the vassal, kneeling before his lord, solemnly vowed to give him service and obedience.

Medieval feudal societies took many different forms. From 1106 to 1135 England was strongly hierarchical, with the king firmly and unmistakably at the summit. In 11th-century France, however, kings had great powers in theory but were often overshadowed by powerful dukes and counts like the Angevins. Certain regions were dominated by these influential vassals but others -- Berry and Picardy, for example -- were split into much smaller units such as viscounties and castellanies (a castle and the land it controlled). Nobles might do homage to their king, but more as a mark of alliance than as an admission of their obligations to him. Such pacts could be, and often were, easily broken when necessary. In the same way, major local potentates made formal deals with their neighbours but regarded these as provisional.