The primary economic system during the Middle Ages in Europe was feudalism. This system was characterized by a hierarchical structure where land was owned by lords who granted portions of it to vassals in exchange for military service and protection. Peasants, or serfs, worked the land in return for shelter and sustenance but had limited rights. Feudalism structured society into distinct classes, with the monarch at the top, followed by nobles, knights, and peasants at the bottom. This system influenced various aspects of life, including politics, economics, and social relations until the rise of more centralized nation-states in later centuries.