vassal
In medieval Europe, a person who paid feudal homage to a superior lord (see feudalism), and who promised military service and advice in return for a grant of land. The term was used from the 9th century.
The relationship of vassalage was the mainstay of the feudal system and declined along with it during the transition to bastard feudalism.
Ceremonial Relationship Between Lord and Vassal
Through the whole remaining part of the day those who had been previously enfeoffed by the most pious Count Charles did homage to the [new] count, taking up now again their fiefs and offices and whatever they had before rightfully and legitimately obtained. On Thursday, the seventh of April, homages were again made to the count, being completed in the following order of faith and security.
First they did their homage thus. The count asked the vassal if he were willing to become completely his man, and the other replied, "1 am willing"; and with hands clasped, placed between the hands of the count, they were bound together by a kiss. Secondly, he who had done homage gave his fealty to the representative of the count in these words, "I promise on my faith that I will in future be faithful to Count William, and will observe my homage to him completely against all persons, in good faith and without deceit." And, thirdly, he took his oath to this upon the relics of the saints. Afterward the count, with a little rod which he held in his hand, gave investitures to all who by this agreement had given their security and accompanying oath.
The oath of fealty
The oath of fealty involved the younger lord, called a vassal, promising support and loyalty to the older lord. The vassal was expected to provide troops, military service, and garrison for the older lord's castle. The vassal was also expected to provide monetary support and advice on any matter the senior lord deemed necessary. The land that a vassal was given was considered to be hereditary, provided that the vassal's conduct and heir were satisfactory.
In return the older lord was obligated to see to the well-being and happiness of his vassals. He couldn't unfairly tax or confiscate lands from a vassal, nor could he allow his vassal to be attacked without sending some sort of military support. The lord was not allowed to attack or plan to kill one of his vassals, nor could he treat a vassal unfairly at court.
If a lord broke the oath, the agreement was considered void and a vassal was free to attack the older lord in retaliation. The Christian Church especially held sanction against breaking of oaths of fealty because the oath was usually sworn at a church in God's name over a holy artifact. The lord's own peers would also act quickly to punish a lord that broke the oath of fealty.
A vassal who was found to have broken the oath would have their lands confiscated. If they attempted to defend their lands, they would usually find themselves going to war against their lord and all their peers. If a vassal felt their lord had broken the oath, they could declare independence and were free to keep their lands or become vassals for another lord. Since most lords saw defiance as rebellion, vassals who declared their independence usually had to have either strong support or be prepared to go to war.
The oath of fealty allowed a single ruler, or sovereign prince, to control vast areas of land by creating vassals among the nobility. The prince would grant tracts of lands, called fiefs, to other members of the nobility called barons in exchange for their allegiance. The barons in turn might grant lands to knights, who swore homage and fealty to the barons and were required to serve them. This system continued down to the level of the serfs, who owed the knights a certain amount of work and crops each year. The king could ask for aid from any of his barons and the barons would send their knights in response.