The concept of just war in Augustine's City of God.
The objective of this work is to examine the just war from the book The City of God. Just war is a controversial concept in Augustinian political philosophy, with war being the extreme resource for conflict resolution between human beings. However, just war implies that one of the conflicting sides wages war based on justice, while the other side does not. Justice, possessed by one of the sides in dispute, will be one of the objects of our analysis in order to understand how a war can be justify as just. We will then deal with peace, since as every war gives rise to the desire for peace at its end; we will see how it is conceived by the citizens of the earthly city and those of the heavenly city, and how, in the final analysis, such a distinction is of paramount importance for the maintenance or not of peace in society. Departing for the investigation of the just war, we will see how this complex concept was present in Augustine's philosophy from his considerations on justice and peace and how, ultimately, he could consider it as something permissible and even desirable under certain circumstances. We will research in particular the Book XIX of The City of God, as well as other books of this work, using for complementary purposes other works by Augustine in our study.