“I’m a son of Saint Augustine …” Pope Leo XIV is the first “Augustinian” pope (i.e., a member of the Order of St. Augustine) of the modern era. In his first speech from the loggia of St. Peter’s Basilica, he presented himself as an heir to the Bishop of Hippo. Since then, the 267th pope has quoted him almost systematically in his speeches and homilies.
I.MEDIA therefore interviewed three leading specialists on this Doctor of the Church to understand what the 5th-century bishop (354-430) could say to the 21st century, and how his thinking could guide the pontificate of Leo XIV.
I. Unity as a central theme
“It seems that during the conclave, the theme of unity was the one that caught the attention of the cardinals. This is an extremely Augustinian theme,” points out Father Jacques Ollier, professor of theology at the Notre-Dame Faculty of the Collège des Bernardins.
St. Augustine expresses this principle of unity particularly in his commentary on Psalm 127 (128). In fact, Leo XIV’s episcopal motto, In illo uno unum – “in him who is one, let us be one” – comes from this text. Unity is therefore first and foremost a matter of faith: it comes from God, who is One in his Trinity—Father, Son, and Holy Spirit—and who gives this unity to humankind. He calls humankind, in turn, to inner unification.
“This unification is the path of conversion that Augustine undertook and recounted in his Confessions,” emphasizes theologian Marie-Anne Vannier. Born into a Christian family in North Africa, Augustine initially was far from the faith. In his youth, he explored pagan religions, notably Manichaeism and Neoplatonism, before embarking on a very long conversion to Christianity.
“He concluded that unity with oneself, this difficult work on oneself, is essential to achieve unity with others, which is the foundation of the Church,” explains the theologian. God “wants us all to be united in one family,” Leo XIV said in his homily at the Mass inaugurating his pontificate, insisting that “in the one Christ, we are one.” Notably, this applies to ecumenism, even though this concept did not exist in St. Augustine’s time, notes Marie-Anne Vannier.
II. Peace against decline
St. Augustine lived in a time of great instability. The Roman Empire, which had been all-powerful for centuries, was reeling from barbarian invasions. The Visigoths sacked Rome in 410, and Augustine narrowly escaped martyrdom. He died in 430 while the Vandals were at the gates of Hippo and Carthage.
Nevertheless, during his lifetime, Augustine didn’t give in to the panic that gripped some of his contemporaries. “As an avid reader of the Gospel, he found in his reading a certainty of a kind of continuity in the disasters that were befalling the world,” notes Father Ollier. But he also knew, as Jesus affirmed, that “deliverance is near.”
Some attributed these disasters to the growing influence of Christianity. In reply, Augustine defended in The City of God the idea that “decadence had already been there for a long time” and that the action of Christians was positive, emphasizes Marie-Anne Vannier.
“He believed that the world’s disorders must be resolved by starting with oneself and with the Church, and therefore by bringing order to the latter—something that Pope Francis began to do and which, I believe, Pope Leo will continue,” says Father Ollier.
Then, he notes, we must strive to extend this peace to the rest of the world, as Leo XIV shows in his messages on Ukraine and the Holy Land. This Augustinian idea of a virtuous circle of peace, which contrasts with pessimistic catastrophism, appears in his first speech in favor of a “unarmed and disarming” peace—that is, an attitude of peace that itself engenders peace.

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III. Prudence and humility
Furthermore, the Augustinian conception of peace found in Leo XIV, notes Jérôme Alexandre, professor of theology at the Notre-Dame Faculty of the Collège des Bernardins, is not an “agreement based on perfect similarity, but the acceptance of differences.” Therefore, it presupposes a certain humility.
Augustine witnessed, in his time, the transformation of the relationship between the Church and the declining Roman Empire. This happened most notably with the signing of the Edict of Thessalonica, in which Emperor Theodosius officially recognized Christianity in 380. But “there is no triumphalism in Augustine,” insists Marie-Anne Vannier.
Having initially studied pagan philosophers, Augustine believed it was necessary for the Church to continue its dialogue with them. “To discern, Augustine listened a lot and took his time; we’ve also seen this temperament in Leo since his election,” she points out.
“Humility is Augustine’s great discovery from the moment of his conversion, to which he constantly returns until his death,” emphasizes Jérôme Alexandre. It finds its origin in the fact that “by becoming incarnate, God Himself chose the way of humility and gave it as an example to men.”
The idea of “Catholicity” as developed by the Bishop of Hippo is “a multifaceted and universal expression of the same faith.” “Augustine is not a dogmatist,” explains Marie-Anne Vannier. She points out that political Augustinianism—which, by opposing the city of God and the city of men in a binary fashion, gave rise to the medieval theocratic perspective—is not faithful to Augustine’s prudence. She quotes his essay On the Trinity:
Let my reader follow me when he shares my certainty, let him search with me when he recognizes his error; when he recognizes mine, let him call me back to him. Thus we will advance together on the path of love, drawing closer to Him of whom it is said: “Seek always his face.”
IV. “With you, I am a Christian”
This Augustinian humility appears in Leo XIV’s conception of the papal mission: “With you, I am a Christian, and for you, I am a bishop,” he declared, quoting St. Augustine in his first speech.
However, the development of the doctrine of Petrine primacy in Augustine’s time was not yet very advanced, Marie-Anne Vannier points out. It was only really defined shortly after Augustine’s death by Pope Leo I (440-461), who defined the pope as “Servant of the servants of God.” “It is therefore difficult to draw lessons from this about how Leo XIV can exercise his ministry,” the theologian points out.
Nevertheless, as a pastor, “Augustine was a man who listened a lot and changed his point of view as he went along,” she notes. She cites as an example the way he approached the question of Pelagian heresy. Jérôme Alexandre also highlights the bishop’s fight against the Donatist schism, “a kind of fundamentalism of his time.”
These challenges continue in other forms in the Church today—especially through strong polarization. In this regard, Leo XIV could follow in the footsteps of St. Augustine by avoiding a “too moralizing tone” or an authoritarian attitude, as Pope Francis has sometimes been criticized for, notes Father Ollier. “In the Confessions, Augustine recalls that he was saved only because God pulled him out of the flames,” he concludes.