The document summarizes the development of feudalism in medieval Europe following the fall of the Carolingian Empire. Invaders like the Vikings, Saracens, and Magyars attacked Europe in the 9th-10th centuries as central authority declined. People turned to local nobles for protection, leading to a system where nobles granted land to vassals in exchange for military service. This new political and social system was called feudalism. Feudalism structured society into nobles, clergy, and peasants and was characterized by relationships of loyalty between lords and vassals.