Feudalism developed in Western Europe between the 9th and 10th centuries as a political, social, and economic system. Power was decentralized as kings granted land to nobles in exchange for military service. Society was strictly stratified with kings, nobles, clergy, and peasants. Peasants or serfs were bound to work lands granted by lords and owed labor services and taxes. The feudal system predominated until the 15th century and was characterized by hierarchies of reciprocal obligations between lords and vassals.