What did vassals promise to a lord under feudalism what d?

Under feudalism, vassals promised loyalty and military service to their lords in exchange for land, known as a fief. They were also expected to provide counsel and support in times of need, often participating in the lord's court and governance. In return, lords offered protection and the right to use the land’s resources, creating a mutually beneficial relationship. This arrangement formed the backbone of medieval society, establishing a hierarchical structure of obligations and alliances.