What To Expect During Pope Leo XIV’s Inauguration Mass

Earlier this week, American Cardinal Robert Francis Prevost was elected as the new Pope of the Catholic Church. Prevost chose the name Pope Leo XIV, becoming the 267th head of the Catholic Church and succeeding the late Pope Francis.

Following this, the Vatican announced that the newly elected Pope would be inaugurated officially into the papacy on Sunday, May 18.

“The Holy See Press Office announced the upcoming schedule for the newly elected Pope Leo XIV. His inaugural Mass will be held in St. Peter’s Square on Sunday, May 18, at 10 am Rome time,” Vatican News stated.

When Pope Leo XIV officially begins his pontificate on May 18, 2025, in St. Peter’s Square, the world will witness one of the Catholic Church’s most symbolic and historic rituals: the Papal Inauguration Mass.

Pope Leo XIV gesturing to the crowd from the balcony of St. Peter's Basilica after he was elected the new Pope on Thursday, May 8, 2025. /VATICAN NEWS

The ceremony will combine centuries-old tradition with modern-day relevance, signalling the start of a new era for over 1.3 billion Catholics worldwide. Viral Tea takes a look at what will happen during the mass:

A Sacred Start: Honouring the First Pope

The day will begin in solemnity. Before emerging to the crowds gathered in the square, Pope Leo XIV will descend to the tomb of St. Peter—the Church’s first pope—beneath St. Peter’s Basilica. This private moment of prayer symbolises the unbroken line of apostolic succession, connecting the new pope directly to Peter.

From St. Peter’s tomb, two essential items will be retrieved: the pallium and the Fisherman’s Ring. The pallium, a white woollen band worn over the shoulders, represents the pope’s role as the shepherd of Christ’s flock. The ring, inscribed with the image of St. Peter casting a net, symbolises the spiritual authority bestowed on each new pontiff.

Procession Into the Square

Following this sacred moment, Pope Leo XIV will be joined by Eastern Catholic patriarchs and representatives of Christian churches in a grand liturgical procession through the basilica and into the open square.

Accompanied by a 14-piece brass ensemble and the chanting of Laudes Regiae—“Christus vincit, Christus regnat, Christus imperat” (“Christ conquers, Christ reigns, Christ commands”)—the scene will echo centuries of papal history and liturgical grandeur.

This is more than pageantry—it is a ritual of continuity, one that announces to the faithful and to the world: the pope has arrived, and his mission begins now.

Receiving the Symbols of the Papacy

At the altar, Pope Leo XIV will receive two traditional symbols of his office. The senior cardinal deacon will place the pallium over the pope’s shoulders, and the senior cardinal bishop will present him with the Fisherman’s Ring. These acts replace the medieval coronation ceremony and reflect the Church’s emphasis on pastoral leadership rather than temporal power.

This shift, first seen in the inauguration of Pope John Paul I in 1978 and solidified under John Paul II and Francis, sends a message: the papacy is a ministry of service, not monarchy.

Oath of Obedience

Immediately following the investiture, six cardinals—two bishops, two priests, and two deacons—will approach Pope Leo XIV to pledge their obedience. This ritual, though abbreviated from earlier centuries, represents the entire College of Cardinals’ unity with and support for the new pope.

The Inauguration Mass: Worship at a Global Scale

The Papal Inauguration Mass will begin shortly after the investiture. Taking place in the vast expanse of St. Peter’s Square, the open-air liturgy will be attended by an estimated 200,000 people, with millions more tuning in worldwide via television and online livestreams.

Fittingly, the Mass will be celebrated on the Feast of St. Joseph the Worker, emphasising humility, integrity, and fatherly care, all qualities the pope is expected to embody.

Liturgical and Cultural Highlights

One unique aspect of the Mass will be the proclamation of the Gospel in Greek. This tradition, reflecting the universality of the Church, honours the Eastern Christian Churches and underscores the Vatican’s ecumenical outreach. The use of both Latin and Greek in the Mass is a nod to the undivided Church of the first millennium.

Pope Leo XIV will deliver his homily in Italian. This moment is expected to draw global attention, as it will likely set the tone for his entire pontificate.

Known for his missionary work in Peru and as the first American pope, Leo XIV may address themes such as poverty, migration, climate justice, and reconciliation. Vatican insiders say the new pope is eager to emphasise inclusion and global solidarity, particularly with youth and the marginalised.

Sacred Music: A Choir of Centuries

Music for the Mass will be drawn from the Church’s rich liturgical heritage. The Vatican Choir will perform Tu es pastor ovium by Palestrina during the Offertory, a Renaissance motet fitting for the occasion—it translates to “You are the shepherd of the sheep.”

The conclusion of the Mass will feature the majestic Te Deum, a hymn of thanksgiving sung in alternating Gregorian chant and a choral setting by Spanish composer Tomás Luis de Victoria.

Communion for Thousands

Approximately 500 priests will assist in distributing Holy Communion throughout St. Peter’s Square, supported by hundreds of volunteers. Logistically, this is a massive operation, but one that the Vatican has perfected over decades. The moment when tens of thousands receive Communion in unison is always one of the most emotionally powerful in any papal liturgy.

Post-Mass Diplomacy: Meeting World Leaders

After the final blessing and recessional, Pope Leo XIV will return to St. Peter’s Basilica to remove his vestments. He will then meet with global dignitaries, including representatives from over 100 nations.

Prince Edward will represent King Charles III of the United Kingdom, while delegations from the United States, Latin America, Africa, and Asia will also be present.

These post-Mass greetings highlight the unique role of the pope—not just as a religious leader, but as a moral voice on the global stage.

Pope Leo XIV speaking to the crowd from the balcony of St. Peter's Basilica after he was elected the new Pope on Thursday, May 8, 2025. /VATICAN NEWS

A Papacy of Hope and Challenge

For many, the inauguration marks more than just a new leader—it signals a new direction. Pope Leo XIV’s background suggests a commitment to justice, dialogue, and ecological stewardship. His emphasis on missionary outreach and his work with Indigenous communities in South America suggest a desire to lead the Church not from behind gilded walls, but from the margins.

By choosing the name Leo—evocative of past reformers and defenders of the faith—he invokes a legacy of courage and bold leadership.

Looking Forward

As Pope Leo XIV steps onto the world stage, he inherits a Church facing both immense challenges and powerful opportunities.

From clergy abuse scandals to plummeting vocations in the West, to explosive growth in the Global South, the Catholic Church stands at a crossroads. How Leo XIV responds—beginning with his message at the inauguration—will shape the Church’s voice for years to come.

But for now, all eyes turn to St. Peter’s Square. In a rite steeped in tradition and charged with meaning, the papacy of Pope Leo XIV begins—not with a coronation, but with a Mass. A message. A mission.