Thomas Head and Richard Landes, eds, The Peace of God: Social Justice and Religious Response in France around the Year 1000 (Ithaca, NY, 1992); Tomaz Mastnak, Crusading Peace: Christendom, the Muslim World and Western Political Order (Berkeley, Los Angeles and London, 2002), pp. 1–18; Duby, Chivalrous Society, pp. 126–31; H. E. J. Cowdrey, ‘The Peace and the Truce of God in the Eleventh Century’, Past and Present, 46 (1970)