What term refers to the relationship established between a lord and his vassal based on mutual obligations?

The term that refers to the relationship established between a lord and his vassal based on mutual obligations is feudalism. In medieval Europe, feudalism was the dominant social and political system where a lord granted land (or a fief) to a vassal in exchange for military service and loyalty. This system was characterized by a network of reciprocal obligations; the vassal owed allegiance, protection, and potentially military support to the lord, while the lord was responsible for protecting the vassal's rights and land.

The relationship was formalized through a ceremony known as "homage," establishing a bond of loyalty. This mutual obligation was the foundation of medieval political structure and significantly influenced social hierarchy and land tenure.

Manorialism, while related, primarily refers to the economic and social system where lords managed their estates and relied on peasant labor rather than focusing specifically on the lord-vassal relationship. Vassalage describes the specific status of the vassal within the feudal system rather than the broader system itself. Serfdom refers to the condition of peasants who were bound to the land they worked on, but it does not encapsulate the mutual obligations between lords and vassals as feudalism