What economic and social system defined medieval Europe, where land was held by lords in exchange for military service?

Feudalism was the dominant economic and social system in medieval Europe, primarily characterized by the relationship between lords and vassals. In this system, lords owned large tracts of land and granted portions of it to vassals or knights in exchange for their military service. This created a hierarchical structure where loyalty and service were exchanged for land and protection.

The essence of feudalism revolved around land as the primary source of wealth and power. Lords would provide land, known as fiefs, to vassals, who in turn owed military support and other obligations. This mutual obligation formed the backbone of the feudal society, influencing not only politics and warfare but also local economies and social structures.

Other systems mentioned, such as mercantilism, capitalism, and socialism, arose in later historical contexts and have different underlying principles. Mercantilism focused on trade and the accumulation of wealth through a nation's commercial interests, capitalism emphasizes private ownership and market-driven economies, and socialism advocates for collective or governmental ownership of production and resources. These systems do not relate directly to the land-based obligations and class structures that defined feudalism in medieval Europe.