This document summarizes the social structure of medieval Europe between the 9th and 16th centuries. It describes the three main social orders of clergy, nobility, and peasants. The clergy comprised the Catholic church and directed the religious life of communities. The nobility were landed owners who held manorial estates worked by peasant villeins or serfs. Peasants lived and worked on manors, providing labor and paying taxes and fees to lords. The document also outlines the rise of knights, monastic orders, and the environmental and economic crisis of the 14th century plague that weakened the feudal system and allowed more powerful monarchs to consolidate their rule.