Table of contents
1. The concepts of war and peace, between history and philosophical and theological speculation - 2. The torment of the Church divided between the praeceptum dilectionis and the natural inevitability of the bellum - 3. Notes on the foundations of the theory of just war in the theology of Saint Augustine and St. Thomas - 4. Ideas on the legal doctrine of the just war in the sources of the ius commune - 5. A look at the main protagonists of the bellum iustum theory in the modern age - 6. The just war in the context of the birth of the international political community – 7. The economic reasons for the war – 8. Pius XII and the international order as a barrier to war drift – 9. The universal peace of John XXIII – 10. Paul VI and the end of the Church of silence – 11. John Paul II , the Pope between the wars: inter arma caritas – 12. Benedict XVI and the proposition of a human ecology of peace – 13. Francis and the definitive denial of any justification for war – 14. Towards a conclusion.

Abstract
The contribution, starting from the foundations of the just war theory of the theology of St. Augustine and St. Thomas, examines the evolution of the pontifical magisterium on the justification of war, culminating with the proposition of a human ecology of peace by Benedict XVI, and with the definitive denial of any justification of conflicts in the reflection of Francis.