During the medieval period, a feudal contract was a contract between a lord and his vassals. The contract consisted of an oath of fealty and defined the obligations of the vassal to the lord as well as the obligations of the lord to his vassals.
Feudalism was the system of rule during the medieval period. The liege lord granted land to a vassal in exchange for service and an oath of fealty. All land was owned directly by the monarch. All lords of the land swore fealty to their king as part of their feudal contract. In exchange for services and military assistance, the king allowed each baron, or lord, to use a set portion of land as his own. The king gave land based on the number of men the lord committed to the king's service and also based on services rendered, familial ties and personal friendships. The lord then gave out land and estates to knights in exchange for an oath of fealty and a contract of military service. In turn, the knight had the right to give plots of land, home and protection to yeomen in exchange for an oath of fealty and service as an infantry man or other non-military service.
As the medieval period progressed, other titles besides barons, knights and yeomen were granted, including dukes and counts, based on the size of the land granted. Additionally, feudal contracts were agreed upon in exchange for things other than military service, including produce, protection and salary.