Augustine on War and Peace
Andrej Zwitter and Michael Hoelzl
A re-reading of Augustine’s theory of war and peace can be fruitfully advanced if we better
understand his comprehensive concept of peace as the harmonic interaction of individuals with each
other, mediated by their relationship with God. After introducing Saint Augustine as peace rather than
just war theorist, we expand on Augustine’s conception of universal peace as laid out in De Civitate
Dei contra Paganos (City of God Against the Pagans, usually simple referred to as Civitas Dei) in its
socio-historical context. Finally we compare Augustine’s theory of universal peace with Kant’s
concept of perpetual peace in his famous and highly influential treatise Zum ewigen Frieden. The
comparison between Augustine and Kant will allow us to see how the vision of a universal peace has
been conceived in theological terms by Augustine and in what ways it has been re-conceptualised in
secular terms by Kant and his vision of a perpetual peace between individuals, between states and
finally perpetual and enduring peace in the world.
St. Augustine (born 354 in Thagaste, today Algeria; died 430 in Hippo Regius, today Algeria) is one
of the four patristic fathers of the Latin Christian Church and from 396 until his death he was Bishop
of Hippo, province of North Africa. Augustine is one of the most influential theologians of all time
and his Civitas Dei (413-26), Confessiones (397-98), De Trinitate (399-414) as well as his studies on
memory and the nature and essence of time have influenced philosophers like Descartes or
Wittgenstein and of course generations of theologians. In short, Augustine’s influence on the
development of Western Philosophy cannot be underestimated. This is also true because Augustine
lived during a period in which Christianity became a universal religion. With Augustine, especially in
Civitas Dei, for the first time a theology for the Empire has been formulated. In addition to his theo-
political ambitions, we find in Augustine some of the most remarkable and honest accounts of a
person’s intimate struggle with the question of what a true belief is and what makes a belief
believable as he elaborates in De Vera Religione.
Augustine is heralded to be the founding father of just war theory. Civitas Dei is Augustine’s only
work that deals with the customs of war and the conditions of peace. However, in Civitas Dei, which
can be seen as a Summa of his theological and philosophical ideas, Augustine surprisingly treats the
topic of just war only marginally. In fact, the context and the purpose of Civitas Dei is a different one.
The book itself is a defense of the City of God (civitas dei) and its role vis-à-vis the City of Man
(civitas terrena). Both cities stand as allegories for the earthly and heavenly realm coexisting in
parallel with the church as mediator between the two. Augustine’s understanding of the Church, as an
earthly community of believers being on a pilgrimage towards the heavenly city of God, has often
Without this dual construction of the Church as being both, terrestrial and heavenly in the making,
Augustine’s Civitas Dei is and was prey to a dualistic, and finally Manichaean understanding of
spirituality and temporality. With this ecclesiological pre-text in mind one has to read his analysis of
just war theory. Providing a theory of just war (bellum justum) is not Augustine’s main aim. In terms
of the person, Augustine is a converted Christian and bishop writing about his theological theory of
the two cities.
To strip, however, Augustine’s thoughts and brief comments on just war from the context of the book,
namely the theological doctrine, would gravely misrepresent Augustine’s ideas. Let us, therefore,
divide Civitas Dei into the traditional separation of just war doctrine into ius ad bellum (the right to
war) and ius in bello (the law in war), and let us add the rather new concept of the ius post bellum (the
law after war). And within this threefold categorization we will try to highlight the theological and
moral contexts (these two cannot be separated in Augustine’s thought) to which they belong.
Ius ad Bellum. Augustine gives hardly any thought to the right to war. In book II chapter 17, he states
that war has to first be declared and that the denial of the Sabines (an italic tribe that lost its
independence to Rome) to give their women to the Romans did not justify the act of war. ‘(T)he wise
man will wage just wars’, as Augustine states in book XIX, chapter 7, but he will still grief over the
great evils and cruelties of war, and thus one can assume he will aim to keep them to a minimum.
Wisdom is one of the classic virtues in the moral theory that lasted until the enlightenment. It is the
key virtue (prudentia) that guides the conduct of all other virtues. Virtues are either gained through
practicing virtuous behavior until it becomes a habit to act virtuously, or virtues that can be inspired.
And this inspiration is an act of God, more specifically an act of the Holy Spirit. Thus, so inspired or
habitually acting in accordance with natural law, the wise man cannot do other than wage a just war.
Furthermore, a just war can only be waged against sin (book 19, chapter 15). And every victory, also
those gained by wicked men, is derived by God’s judgment of whether the vanquished to be humbled
or for removing or for punishing their sins. In other words, the cause of war can only be the sin of
man. Its purpose is the extension of the virtuous kingdom as necessary consequence if the alternative
would be that empires ruled by wicked man would otherwise threaten the peace. He thus allows for
just wars as a response to a wrong (causa iusta) and which leads to extending one’s empire, under the
condition that this empire leads to a stable peace (intentio recta).
Augustine, however, states that a peace based on neighborly concord between many small kingdoms
would best resemble the city of God, which would be most conducive to a lasting peace (book IV,
chapter 15). As we will see later on in Kant’s conception of perpetual peace (specifically in the
second definitive article) there is a striking resemblance between Augustine’s divine pluralism and
Kant’s view of a federal community of states when he outlines the conditions of the possibility for
international law (ius gentium).
Ius in Bello. The first few chapters of Civitas Dei deal with the customs of war. However, differently
than one might expect, Augustine does not lay down the rules that would apply during war. Rather,
what becomes immediately clear, Augustine’s argument is that the customs of war knows no limits,
but cruelty and slaughter constitute the customs in the conduct of war. The sacking of Troy (book I,
chapters 2-4) serves Augustine as a prime example that the status of kingship did not protected
Priamos, and neither did his fleeing into the sanctuary of the temple protect him from being
slaughtered by the Greeks. In chapter 5, Augustine refers to Caesar’s own words in the senate to
illustrate that nobody should view the customs of war during this period as anything but cruel:
Even Cæsar himself gives us positive testimony regarding this custom; for, in his deliverance in the senate about
the conspirators, he says (as Sallust, a historian of distinguished veracity, writes ) that virgins and boys are
violated, children torn from the embrace of their parents, matrons subjected to whatever should be the pleasure of
the conquerors, temples and houses plundered, slaughter and burning rife; in fine, all things filled with arms,
corpses, blood, and wailing.
In contrast to these customs of war very much as an exception to the norm, Augustine points out
(book I, chapter 6) that the Romans were famed for behaving particularly well mannered in war. They
were claimed to spare the vanquished, to forgive injury rather than to seek revenge, and to exempt
temples from plunder and spare those who were seeking refuge there. Augustine, however, illustrates
that the reality is farther from the fame. Particularly Marcus Aurelius, which Augustine describes as a
‘poster child’ in war, serves as example that despite his commands that no free people should be slain
the city of Syracuse was sacked according to the customs of war. The treatment of the customs of war
serves Augustine not only to illustrate that war is cruel, but also that Christianity exerts a civilizing
effect on war through inspiring virtues and that Christ’s power even inspires the barbarians.
Ius Post Bellum. A victory in a just war leads to peace and in the case of Augustine’s theory should
lead to universal peace. The concept of universal peace is much more complex than, for example, the
contemporary concept of ‘positive peace’ as advocated by Johann Galtung. Galtung understands
‘positive peace’, in a way reminding of Thomas Hobbes, as absence of structural and cultural violence
opposed to ‘negative peace’ in the sense of absence of direct violence only. In Leviathan (book II, ch.
XIII), Hobbes famously states:
For as the nature of foul weather lieth not in a shower or two of rain, but in an inclination thereto of many days
together: so the nature of war consisteth not in actual fighting, but in the known disposition thereto during all the
time there is no assurance to the contrary. All other time is peace.
It is in regard to peace that the fundamentally theological dimension of Augustine’s treatment of just
war becomes completely evident (book 19, chapter 13):
The peace of body and soul is the well-ordered and harmonious life and health of the living creature. Peace
between man and God is the well-ordered obedience of faith to eternal law. Peace between man and man is well-
ordered concord. Domestic peace is the well-ordered concord between those of the family who rule and those who
obey. Civil peace is a similar concord among the citizens. The peace of the celestial city is the perfectly ordered
and harmonious enjoyment of God, and of one another in God. The peace of all things is the tranquillity of order.
(…)As, then, there may be life without pain, while there cannot be pain without some kind of life, so there may be
peace without war, but there cannot be war without some kind of peace, because war supposes the existence of
some natures to wage it, and these natures cannot exist without peace of one kind or other.
To understand the complexity of Augustine’s thought, we need to take a look at the logic of virtue
ethics vis-a-vis politics. In contrast to our contemporary understanding of the difference between
politics and morals, such an understanding was foreign to the classic virtue ethicists. For Aristotle,
ethics was the art of living well as an individual and politics the art of living well of a society and the
art of ruling well of this society. The key concept is eudaimonia – that is flourishing and wellbeing.
With pax universalis Augustine introduces reinterpretation of eudaimonia. Universal peace is thus not
only to be understood as a mono-dimensional peace, as a common understanding of peace between
two states would suggest.
First, it is a peace that requires first the peace within man (a harmony of body and soul), then a peace
between man and God. Augustine defines this latter peace as man acting in accordance with God’s
eternal law; that is the law, in contrast to man’s law and natural law, which is only known to God and
which can only be approximated but never be perfectly understood through man’s conduct of reason.
In his apt formula Augustine juxtaposes the two laws as man living by the love of God (in both
meanings, genitivus subjectivus and genetivus objectivus) to man living by the love of man.
Augustine continues to introduce, next to the virtue ethical and theological dimensions of peace, a
political dimension of peace – the well-ordered concord between man and man. This well ordered
concord is a quality that applies to different forms of relationships: in the family as domestic peace
and within the state (a first allusion to social contracts) as civil peace. In chapter 15 of book IV
Augustine extends this universal peace based on well-ordered concord also to kingdoms amongst each
other. The condition of the well-ordered concord between kingdoms can, therefore, be seen as a
precursor to Kelsen’s Grundnorm known as the principle dominant in Roman Law ‘pacta sunt
servanda’. Finally Augustine adds the spiritual dimension to universal peace, which goes far beyond
classic eudaimonia in being the ‘harmonious enjoyment of God, and of one another in God.’ This
harmony in and through God encompasses the tranquility of order and can only be enjoyed in the
tranquility of order. Vis-à-vis God this order based on obedience of faith and vis-à-vis man (read:
equals) it is based on concord.
When Augustine says that the existence of peace is the condition of the possibility of war to exist, he
argues this analogous to the classical idea of evil as the privation of good (privatio boni – book XII
chapter 9:‘For evil has in itself no substance, rather the loss of what is good had received the name
evil’); Subsequently, Augustine defines war as a privation or corruption of peace. This idea goes back
to Aristotelian and Platonic thinking that a thing is called good if it fulfills its nature and bad if it falls
short of fulfilling its perfect form.
In other words, Augustine understands peace as the state of nature, quite in contrast to Hobbes, who
sees the fight of one against the other as the state of nature. This view of Augustine stems from the
fact that he imagines all things created by God as per se created as good and corrupted through the
acts of others. This should suffice to show that neither peace nor (just) war nor politics in Augustinian
thought can be understood independently of his theology.
Turning to Immanuel Kant’s essay on perpetual peace, no other individual piece by Kant has been
more often reproduced than this essay. No other individual piece by Kant has been more often
reproduced than this essay. With some witty irony Kant imitates the legal structure of a peace treaty
by dividing the essay into two main sections and two appendices, the latter being added to the second
edition of 1797. The first part comprises six preliminary articles (Präliminarartikel) defining the
absolute ‘must not’ commands in international law: 1) No peace should be made if the peace treaty
serves as the basis of a future war; 2) No state should be consumed by inheritance, exchange,
purchase or bestowment; 3) Standing armies (miles perpetuus) should be eliminated in the future; 4)
No fiscal dependencies should be made which interfere with international affairs; 5) There should be
no political interference with the business of other states; and 6) No state during wartime should
commit acts, which make a mutual peace treaty in future impossible (e.g. breach of capitulation,
espionage, use of poison etc.).
The second part comprises three definitive articles in which Kant distinguish positively between three
dimensions of the conditions of the possibility of perpetual peace. They are; 1) On a constitutional
level only a republican state can guarantee peace; 2) On the level of international law a feral union of
sovereign states must be established which, on the one hand protects the particularity and sovereignty
of each member and, on the other functions as collective authority without any primus inter pares; 3)
Finally, global civil rights (Weltbürgerrecht) should be limited to the conditions of general
Within the scope of this essay we will not have space to analyse the brilliant and complex appendices
of the Friedenschrift in detail. We would have to examine Kant’s distinction between the figure of a
moral politician juxtaposed to the figure of a moralizing politician, to elucidate the role nature plays
in supporting the possibility of a perpetual peace, the importance of duty and obedience to a priori
universal moral norms and finally to discuss Kant’s ‘transcendental and positive principle of public
law’, that is publicity.
We would rather like to limit our comparison to Kant’s explicit reference to Augustine in the first
addition to the third definitive article entitled, ‘On the guarantee of perpetual peace’. In this part of the
treatise the author raises the question how perpetual peace can be ensured. Given the obvious
wickedness of man and accepting Hobbes negative anthropology of ‘war of every man against every
man’, the problem is to demonstrate the possibility of peace. In an extensive footnote Kant, discussing
nature as opposed to free will, alludes to Augustine (Confessions 12, 18) distinguishing between three
types of providence: foundational providence (providential conditrix; semel iussit, simper parent),
governing providence (providential gubernatrix) and leading providence (providential directrix).
What is important here is, that for Kant, it is nature which is divinely inspired and which ultimately
enables us to reach a state of perpetual peace.
In Augustine, on the contract, peace was always seen as gift from God. Peace, in the end is grace. In
Kant’s conception of perpetual peace, nature provides the grounds for peace because of its ‘divine
providence’. This can be best illustrated by the reason Kant gives for the peace preparing role nature
place outlined in the three definitive articles. On the level of constitutional law peace is possible
because, by nature, human beings should act according to moral law and that implies that if they
ought to act according to moral law, they can act according to moral law. On the level of international
law, nature has made the family so diverse in languages, religious beliefs, customs and attitudes so
that this plurality prevents hegemony and the despotism of one single political unity. Finally, on a
global level, nature, according to Kant, provides the grounds for peace because it has implanted in
human beings the desire to trade with each other. Therefore, so the optimistic view of Kant, global
trade prevents the outbreak of non-economically stimulated conflicts. At least, the last premise can be
More important though, than the grounding function of nature in warranting perpetual peace is the use
of practical reason. If the former was the objective condition for perpetual piece, than the latter is the
subjective condition of peace. In the end, everything depends on the moral politician who follows the
a priori moral law of practical reason and who is assured to be supported by nature’s providence.
What we can see in Kant’s work is a remarkable transformation of Augustine’s understanding of
peace as divine gift. With Kant and, one might say with modernity, the agent of peacemaking is no
longer God but man while the tool of peacemaking, namely concord, remains the same. The church,
as community simul iustus et peccator (being justified and sinner at the same time), at the same time
temporal and spiritual on its pilgrimage to becoming the city of God and therefore towards universal
peace inspired by God has been transformed to the community of global citizens guided by the
universal moral law instilled through practical reason. The state is seen in Kant as singular entity as
opposed to classical virtue ethics related philosophy, which saw a need for the autonomy of individual
morality and its incommensurable role in politics. Even without taking into consideration the
theological dimension advocated by Augustine, universal peace goes beyond perpetual peace insofar
as perpetual peace is a negative peace – an absence of war. It cannot be much more as Kant’s vision
of humanity and its state of nature is inherently Hobbesian, whereas the Augustinian state of nature is
peace by God’s grace and creation. But both see similarly the central role of practical reason (in terms
of virtue ethics phronesis or practical wisdom) in the process of reaching from war to peace.
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Marcus Dods. From Nicene and Post-Nicene Fathers, First Series, Vol. 2. Edited by Philip Schaff.
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