Feudal fragmentation in historical science call the special period of weakening of the central power of the monarch in the feudal states. The feudal fragmentation is most characteristic of the early Middle Ages when economic and military strengthening of large feudal lords in the conditions of the senyorialny system of organization of labor led to emergence of a set of lands, small, almost independent of the central power, – feuds.
Formation of feudal fragmentation was promoted in many respects by prevalence of subsistence economy in economy of feudal destinies and poor development of commercial and political connections. The specific system of a compulsory military service at which each feudal lord – the owner of a large allotment, had an opportunity to create own military units from the vassals and peasants living on its lands had not smaller value. Chronologically feudal fragmentation in the countries of Europe covers the period since the 9th century (from the section of the central power in Charles the Great's empire) till the 16th century when in the created centralized states the last destiny was liquidated. In Ancient Russia the feudal system began to develop a little later therefore also the period of fragmentation of Kievan Rus' attacked specific principalities later – approximately from the first half of the 12th century. The feudal fragmentation was natural result of the logic of development of early feudal society. In the course of growth and a branching of a ruling dynasty the number of applicants for the power increased more and more. Representatives of the royal family actively broadened the territories, collected a quitrent from local community, increased the army at the expense of a compulsory military service. Thus, gradually the power of the monarch was more and more substituted for the power of large feudal lords until became almost nominal. Peripheral military resources considerably increased while administrative opportunities of the central power decreased. Full development of a feudal system at which an overwhelming part of ordinary feudal lords began to need the uniform spokesman of the views and interests became the main prerequisite of the termination of feudal fragmentation. There was a need for the general leader. Unlike large landowners, average and small feudal lords supported the royalty in its fight against the patrimonial aristocracy for territorial integrity more often. Exactly the average and gentry made the main force of royal armies. It played a significant role in formation of the uniform centralized states.