“A subject peasantry; widespread use of the service tenement (i.e. the fief) instead of a salary, which was out of the question; the supremacy of a class of specialized warriors; ties of obedience and protection which bind man to man and, within the warrior class, assume the distinctive form called vassalage; fragmentation of authority-leading inevitably to disorder; and, in the midst of all this, the survival of other forms of association, family and State, of which the latter, during the second feudal age, was to acquire renewed strength.” — Marc Bloch, La Societe’ feodale. cited in Brown, “Tyranny of a Construct”
“a body of institutions creating and regulating the obligations of obedience and service-mainly military service-on the part of a free man (the vassal) towards another free man (the lord), and the obligations of protection and maintenance on the part of the lord with regard to his vassal. The obligation of maintenance had usually as one of its effects the grant by the lord to his vassal of a unit of real property known as a fief.” — F.L. Ganshof, Feudalism, cited in Brown, “Tyranny of a Construct”
“in political terms, feudalism is marked by a fragmentation of political authority, private possession of public rights, and a ruling class composed (at least originally) of military leaders and their followers.” — Joseph Strayer, “The Tokugawa Period and Japanese Feudalism,” cited in Brown, “Tyranny of a Construct”
“feudalism The social organization created by exchanging grants of land or fiefs in return for formal oaths of allegience and promises of loyal service; typical of Zhou dynasty and European Middle Ages; greater lord provided protection and aid to lesser lords in return for military service.” (Stearns, et al., G-5)
“On the whole, European feudalism inhibited the development of strong central states, but it also gradually reduced purely local warfare. … kings could use feudalism to build their own power.” (Stearns, et al., 334)
I think maybe you need S. Reynolds, Fiefs and Vassals, too!