Introduction : methodology of this project / Beatrice Heuser and Anja V. Hartmann -- History and international relations theory / Andreas Osiander -- Pt. I. War and peace in classical antiquity. Introduction / Hans van Wees and John Rich -- War and peace in ancient Greece / Hans van Wees -- Greeks and Persians : West against East / Simon Hornblower -- Warfare and external relations in the middle Roman Republic / John Rich -- Roman-Carthaginian relations : from co-operation to annihilation / Ruth Stepper -- Pt. II. War, peace and faith in the Middle Ages. Introduction / Julian Chrysostomides and Beatrice Heuser -- Byzantine concepts of war and peace / Julian Chrysostomides -- Collective identities, war and integration in the Early Middle Ages / Bernhard Zeller -- Warfare in the Middle Ages / Jan Willem Honig -- The crusading movement / Jonathan Riley-Smith -- War, peace and national identity in the Hundred Years' War / Anne Curry -- Pt. III. War and peace in Early Modern Europe. Introduction / Anja V. Hartmann -- Wars of religion : the examples of France, Spain and the Low Countries in the sixteenth century / Aline Goosens -- Identities and mentalities in the Thirty Years' War / Anja V. Hartmann -- Interstate war and peace in Early Modern Europe / Heinz Duchhardt -- Pt. IV. The era of ideological wars. Introduction / Beatrice Heuser -- The revolutionary period, 1789-1802 / Marc Belissa and Patrice Leclercq -- From Volkskrieg to Vernichtungskrieg : German concepts of warfare, 1871-1935 / Robert T. Foley -- Enemy image and identity in the Warsaw Pact / Michael Ploetz -- Conclusions / Beatrice Heuser and Anja V. Hartmann.