Feudalism or Vassalage is a medieval contractual relationship among the upper classes, by which the ruler of the land grants land (also called fiefs) to his certain deserving persons (the vassal) in return for military service, tithes and suchlike.
Lord and vassal are interlocked in a web of mutual rights and obligations, to the advantage of both. Whereas the lord owes his vassal protection, the vassal owes his lord military and other services. The lord was expected to provide a court for his vassals who in turn were to provide the lord with counsel before he undertook any initiative of importance to the feudal community as a whole, such as planning a crusade. In addition the lord frequently convened his vassals "to do him honor."
Financial benefits accrued largely to the lord. A vassal owed the lord a fee knows as relief when he succeeded to his fief, was expected to contribute to the lord's ransom were he captured and to the lord's crusading expenses, and had to share the financial burden when the lord's eldest son was knighted and his eldest daughter married.
The rights and obligations between each ruler and his vassal is dependent on the rules of the kingdom upon which they reside.