How does a vassal function in a feudal system?

In a feudal system, a vassal is a subordinate who receives land, known as a fief, from a lord in exchange for allegiance and military service. The vassal is obligated to support the lord, often by providing troops or resources during times of conflict. In return, the lord offers protection and the right to govern the land, creating a reciprocal relationship that underpins the social and political structure of feudalism. This system fosters loyalty and hierarchy within medieval society.