The word vassal is believed to have been derived from the Medieval Latin term vassallus, the Roman and Latin term vassus, meaning servant, and the Celtic and Welsh term gwas, which means a young man who is a servant or feudal tenant.
Vassals in the Middle ages were those who held the land, called a fief, and owed service and allegiance to the lord who granted them that land. The vassal was usually a knight or a baron, but could also be a member of the clergy or a trusted member of nobility. Vassals in the Middle Ages were an integral part of feudalism, which was the system of government throughout Europe in the Middle Ages.