St. Catherine of Siena: Mystic, Tertiary, and Defender of the Church

Fr. Scott Haynes

Introduction: A Saint for Our Times

Born in 1347 in Siena, Italy, during the devastation of the Black Death, Saint Catherine of Siena lived in an era of deep social, political, and ecclesiastical turmoil. Yet, she emerged from obscurity to become one of the most luminous figures of the Church. A woman of no formal education, no ecclesiastical rank, and no family wealth, Catherine exerted unparalleled spiritual and political influence in the 14th century. Through the force of her holiness, mystical union with God, and fearless truth-telling, she became a reformer of the Church and confidante to popes.

Mystic from Childhood: Union with Christ the Bridegroom

From her earliest years, Catherine had visions of Christ and the saints. At just six years old, while walking near the Dominican Church of San Domenico, she saw Christ in glory seated with Saints Peter, Paul, and John, wearing papal robes and smiling at her. She later said this vision left such an impression that she resolved to give her entire life to God (Bl. Raymond of Capua, The Life of St. Catherine of Siena, 1.3).

Despite her parents’ wishes that she marry, Catherine, by the age of twelve, had privately taken a vow of virginity. Her family resisted violently—especially her mother, who subjected her to harsh labor and humiliation. Catherine responded not with rebellion but silence and humility. Eventually, her parents relented, and at sixteen, she was allowed to join the Third Order of St. Dominic, known as the "Mantellate." This group of lay Dominican women typically served the sick and lived lives of piety at home. Her decision to live her vocation in her family house rather than entering a convent was radical and would become part of her unique spiritual witness.

It was during this hidden period—three years spent largely in prayer, fasting, and interior silence—that Catherine experienced a profound mystical union with God. She had frequent ecstasies and visions, and her soul was mystically united to Christ in what is called her “spiritual espousals.”

Later, she would experience a deeper transformation—her “Mystical Marriage” with Christ—in which she received an invisible wedding ring made of Christ’s own flesh (Dialogue 132). She claimed she could always see the ring, though others could not. It was a sign of total and permanent union. This experience echoes the words of Hosea: “I will betroth you to me forever” (Hos. 2:19), and set the tone for Catherine's radical obedience to divine inspiration.

Her Vocation as a Lay Dominican: In the World, Not of It

Despite being a laywoman, Catherine lived more austerely than many religious. She practiced intense fasting, surviving for long periods on the Eucharist alone, which she described as her “only food.” She wore a hair shirt and scourged herself daily. She slept little, often only one hour a night, and spent the rest in prayer.

Yet her asceticism was not an end in itself—it was the fruit of her burning love for God and her desire to suffer in union with Christ. She saw suffering as a way to participate in the redemption of souls. “Let us suffer with Christ,” she wrote, “and we shall rejoice with Him” (Letter 83).

Though she began in solitude, Catherine was soon surrounded by followers—priests, nuns, nobles, artists, scholars, and even hardened sinners—who came to her for counsel. They called themselves her “family,” and Catherine led them with spiritual authority, though she remained humble and referred to herself as “servant of the servants of Jesus Christ.” Her home became a de facto spiritual center.

Dialogue with God: Her Major Work

At the height of her mystical life, Catherine dictated her famous work, The Dialogue of Divine Providence, to her secretaries while in states of ecstasy. In this profound spiritual text, God the Father speaks to the soul, instructing her in the way of divine love, humility, obedience, and charity. Themes such as divine mercy, the value of suffering, and the role of Christ as the Bridge between heaven and earth permeate the Dialogue.

The Father tells Catherine:

“Everything I give to man is done with justice and mercy… I created you without you, but I will not save you without you.” (Dialogue, 4)

Catherine’s Dialogues reveal her as a theologian of remarkable depth, though she had no formal education. She was taught by the Holy Spirit in what she called the “cell of self-knowledge,” a mystical place within the soul where one meets both their own weakness and the mercy of God.

Defender of the Church and Advocate for the Papacy

One of the most astonishing aspects of Catherine’s life is her involvement in the highest levels of ecclesial politics. At a time when the papacy was weakened and discredited, she emerged as a passionate advocate for reform.

In the 14th century, the Papacy had been moved from Rome to Avignon, where it had remained for over 70 years under French influence. Catherine perceived that the Church was suffering not only from external political pressures but from internal corruption and spiritual decay.

She wrote scathing yet loving letters to Church leaders, bishops, and even to Pope Gregory XI, exhorting them to repentance and courageous action. To Gregory, she wrote:

“Be manly in your action, not fearful. Answer God who is calling you to come and occupy the seat of blessed Peter in Rome!” (Letter to Pope Gregory XI, ca. 1376)

In 1376, she traveled to Avignon herself and met with Gregory XI. Her presence and words so moved him that, after considerable resistance, he returned the papacy to Rome—a historic turning point.

Later, during the Western Schism (1378), when rival claimants to the papal throne split the Church, Catherine supported Urban VI, urging unity and fidelity even when other prominent figures broke away. Her defense of the legitimate pope cost her friendships and caused her deep suffering. Still, she never wavered.

Her Final Years: Consumed by Love

In her final years, Catherine offered herself as a victim for the Church, praying for unity and purification. Her body weakened from years of fasting and penance. She received the stigmata in 1375, though it remained invisible at her request. Her soul burned with love for God, and she often entered ecstasy for hours or days.

She died in Rome on April 29, 1380, at the age of 33, the same age as Christ. Her final words were, “Father, into Your hands I commend my spirit.”

Legacy: Canonized, Venerated, and Declared a Doctor

In 1461, Pope Pius II canonized Catherine. In 1939, Pope Pius XII declared her one of the patron saints of Italy, alongside St. Francis of Assisi. In 1970, Pope St. Paul VI named her a Doctor of the Church, one of only four women (as of 2024) to receive this title, recognizing the theological profundity of her writings.

Her relics are divided: her body lies in Rome at Santa Maria sopra Minerva, and her head is enshrined in Siena’s Basilica of San Domenico.

Saint Catherine’s Message Today

Catherine speaks with clarity across the centuries. Her life challenges modern believers to reject mediocrity and embrace the Gospel with total fervor. She calls each Christian—priest, layman, mother, scholar, politician—to interior renewal and holiness.

In a time when the Church again faces internal crisis and external opposition, Catherine’s voice is both a rebuke and a consolation. Her call for fidelity to Christ, courageous leadership, and trust in divine providence remains as urgent now as in the 14th century.

She wrote:

“If you are what you should be, you will set the world on fire.” (Letter T368)

And she lived those words, consuming herself in divine love and becoming a flame that still burns.

Selected Quotes from St. Catherine of Siena

On love of God: “Love transforms one into what one loves.” (Dialogue, 60)
On obedience: “It is not he who begins, but he who perseveres who will be saved.” (Letter to Brother Matteo)
On the Church: “The Church is not built on human beings, but on Christ.” (Letter 28)

Citations

Raymond of Capua, The Life of St. Catherine of Siena, trans. George Lamb (London: Harvill Press, 1960).
St. Catherine of Siena, The Dialogue, trans. Suzanne Noffke, O.P. (New York: Paulist Press, 1980).
St. Catherine of Siena, Letters, various translations including those by Noffke and Thorold.
Benedict XVI, “General Audience on St. Catherine of Siena,” Nov. 24, 2010.
Pope St. Paul VI, Laudem Gloriae, proclamation of Doctor of the Church, 1970.

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