Pope Leo’s Motto and Coat of Arms Pay Homage to St Augustine

by CNS · May 13, 2025

Main: Pope Leo XIV greets photographers as he welcomes members of the media who covered his election, during a meeting in the Paul VI Audience Hall at the Vatican May 12, 2025. (CNS photo/Lola Gomez. Inset: Pope Leo XIV’s coat of arms with his episcopal motto, “In Illo uno unum,” literally “In the One (Christ), we are one,” is seen in an image published by the Vatican Secretariat of State on May 10, 2025. (CNS photo/Vatican Media)

By Catholic News Service, CNS – Pope Leo XIV’s devotion to St Augustine, his life and ministry as a member of the Augustinian order and his focus on the unity of the church are reflected in his episcopal motto and coat of arms.

When he appeared on the balcony of St. Peter’s Basilica shortly after his election on May 8, he introduced himself as “an Augustinian, a son of St Augustine.”

And he explained that the cardinals who elected him “have chosen me to be the Successor of Peter and to walk together with you as a Church, united, ever pursuing peace and justice, ever seeking to act as men and women faithful to Jesus Christ, in order to proclaim the Gospel without fear, to be missionaries.”

His episcopal motto is, “In Illo uno unum,” or literally “In the One, we are one.”

Vatican News explained that the phrase is taken from St Augustine’s “Exposition on Psalm 127,” where he explains that “although we Christians are many, in the one Christ we are one.”

As a cardinal, he told Vatican News in 2023, “As can be seen from my episcopal motto, unity and communion are truly part of the charism of the Order of St Augustine, and also of my way of acting and thinking.”

“I believe it is very important to promote communion in the church, and we know well that communion, participation and mission are the three keywords of the Synod” of Bishops on synodality, he said. “So, as an Augustinian, for me promoting unity and communion is fundamental.”

His shield, now topped by a mitre instead of the red galero hat on the shield of cardinals, is divided diagonally into two. The upper half features a blue background with a white lily or fleur-de-lis, symbolising the Virgin Mary, but also his French heritage.

The lower half of the shield has a light background and displays an image common to the religious orders named after and inspired by St Augustine: a closed book with a heart pierced by an arrow.

Vatican News said, “This is a direct reference to the conversion experience of St. Augustine himself, who described his personal encounter with God’s word using the phrase: ‘Vulnerasti cor meum verbo tuo’ – ‘You have pierced my heart with your Word.'”