Feud
According to medievalist Marc Bloch, "The Middle Ages, from beginning to end, and particularly the feudal era, lived under the sign of private vengeance. The onus, of course, lay above all on the wronged individual; vengeance was imposed on him as the most sacred of duties ... The solitary individual, however, could do but little. Moreover, it was most commonly a death that had to be avenged. In this case the family group went into action and the faide (feud) came into being, to use the old Germanic word which spread little by little through the whole of Europe--'the vengeance of the kinsmen which we call faida''', as a German canonist expressed it. No moral obligation seemed more sacred than this ... The whole kindred, therefore, placed as a rule under the command of a chieftain, took up arms to punish the murder of one of its members or merely a wrong that he had suffered" (Marc Bloch, trans. L. A. Manyon, Feudal Society, Vol. I, 1965, p. 125-126).