A vassal is a person in the feudal system who has pledged loyalty and service to a lord in exchange for land or protection. This relationship was common in medieval Europe, where vassals would manage the land and provide military support when needed. In return, they received security and the right to work the land. Vassals were often knights or lesser nobles who held a fief, which is a piece of land granted by their lord. This system created a hierarchy, with the king at the top, followed by lords, and then their vassals. The arrangement helped maintain order and stability during turbulent times.