First millennial saint, Italian teenager Carlo Acutis, spread Catholicism online

The Catholic world has gained its first millennial saint.

Saint Carlo Acutis, an Italian teenager who tragically died in 2006, has been canonised by Pope Leo XIV in a ceremony at the Vatican, giving the next generation of Catholics a relatable role model who used technology to spread the faith.

Pope Leo canonised Saint Carlo during an open-air mass in St Peter's Square that was attended by tens of thousands of people, many of them millennials and couples with young children.

During the first saint-making mass of his pontificate, Pope Leo also canonised another popular Italian figure who died young, author Pier Giorgio Frassati.

The Vatican said 36 cardinals, 270 bishops and hundreds of priests had signed up to celebrate the mass along with Pope Leo in a sign of the saints' enormous appeal to the hierarchy and ordinary faithful alike.

A hour before the mass, St Peter's Square was already full with pilgrims, many of them young millennial Italians who had found in Saint Carlo a relatable role model.

Many of his fans are celebrating the day in person and online, sharing prayers and adorning themselves with saintly merch.

The late Pope Francis had planned to canonise Saint Carlo in April during the Jubilee of Teenagers, a special weekend to celebrate young followers of Christ.

However, the Pope's death on Easter Monday and the subsequent mourning and conclave periods delayed the proceedings.

On June 13, Pope Leo announced that Saint Carlo Acutis and Saint Pier Giorgio Frassati, would be the first saints named in his pontificate.

Saint Carlo, who is known as the "saint in sneakers", has been touted as the patron saint of the internet for his work cataloguing miracles and evangelising online.

And with Catholicism on the decline in many countries, including Australia, some are hoping a relatable saint will help galvanise the next generation of Catholic youth.

Who was Carlo Acutis?

Born in London in 1991 but raised in Milan, Saint Carlo loved gaming, computer programming, soccer, Pokémon, and his dog Billy.

While neither of his parents were religious before he was born, he identified as a devout Catholic from an early age and devoted his life to sharing his love of Jesus.

He was particularly passionate about Eucharistic miracles: supernatural events involving consecrated bread and wine as the literal body and blood of Jesus Christ.

At 11 years old, he created an interactive website cataloguing these miracles around the world. It is still accessible today, and has been displayed as an exhibition on five continents.

He also catalogued visions of the Virgin Mary and built websites for religious causes.

While he loved his PlayStation, he limited himself to playing just one hour a week to ensure his focus remained on God.

Father David Ranson, the parish priest at Our Lady of Dolours church in Sydney, which displays a relic of Saint Carlo's — two of his hairs — in a shrine, says in many ways he was an "ordinary young man".

"But he was a very passionate young man, full of life," he tells ABC Radio National's Soul Search.

"He had a great vitality about him … For a young man, it was a very full life."

In October 2006, the 15-year-old developed pain in his throat and quickly became seriously ill.

Soon after, he was diagnosed with acute promyelocytic leukemia, a rare and aggressive blood cancer, and died within a week.

It was his wish to be buried in the central Italian town of Assisi, the birthplace of the highly venerated 13th-century Catholic friar, Saint Francis.

Acutis identified with Saint Francis' values of poverty, chastity and obedience, as well as his patronage of animals and the environment.

This admiration was shared by the late Pope Francis, who took his papal name in honour of the same saint.

Followers of Saint Francis were historically "not afraid to get their hands dirty", explains Joanne Pierce, professor emerita in the department of religious studies at the College of the Holy Cross.

"They were very willing to help out … They were doers, but they spread the message, and I think that's one of the things that Carlo Acutis was so devoted to," she says.

"Carlo gave out sleeping bags to the homeless, he would give the poor money from his own allowance. He also protected other kids from being bullied."

The miracles that led to sainthood

Father Ranson says Saint Carlo's impact was clearly visible on the day of his funeral.

"There was an unexpected crowd of people from all over Milan; basically, the poor and the homeless," he says.

"It became apparent that Carlo had befriended so many of these people."

Saint Carlo's body was moved to Assisi's Sanctuary of the Renunciation a year after his death.

In 2013, the Archdiocese of Milan opened a formal request to consider him for canonisation.

Pope Francis declared him venerable in 2018 — a significant step towards sainthood — and two years later, the church officially recognised a miracle attributed to Acutis.

He is believed to have cured a young Brazilian boy with a serious birth defect in 2014.

This led to his beatification, the Catholic Church's proclamation that a deceased person has entered heaven and can be publicly venerated.

After the beatification ceremony, Saint Carlo's relics and tomb were opened to the public.

The young saint's body was encased in wax to preserve his likeness, and he was laid to rest in jeans, a jacket and Nike sneakers. A live stream of the tomb is available to view online.

Saint Carlo is believed to be responsible for another miracle: healing a Costa Rican woman after a life-threatening bicycle accident in 2022.

On September 7, he was officially canonised and declared a saint.

A relatable saint

Where most saints throughout history were theologians, missionaries or members of clergy, Saint Carlo broke the mould.

"His life shows that a true faith in God, a true faith in Jesus Christ doesn't mean that you don't get to have a normal life and be a normal teenager," Professor Pierce says.

Antonia Pizzey, a lecturer in theology at Australian Catholic University, says Saint Carlo speaks to "younger people today".

"People who have grown up with the climate crisis, who have grown up with the internet," she says.

Saint Carlo's methods of outreach inspired other young Catholics, too.

In the past few years, several documentaries have been made about him, including one chronicling his influence on young American Catholics making a pilgrimage to the Vatican.

This year, three Irish teenage brothers even created a Lego short film about his life.

Father Ranson says the young saint demonstrated that "holiness is not something only reserved for the past".

"He's such a wonderful example to young people that even as children or adolescents, it's possible to draw close to God and to have a heart that's open to something transcendent."

'God's influencer'

Saint Carlo is not the first patron saint of the internet. Saint Isadore of Seville was also given that title by Pope John Paul II in 1997.

Born around 1,400 years before the invention of the computer, Saint Isadore was a scholar, theologian and archbishop who meticulously catalogued human knowledge in a 20-volume encyclopedia.

However, Saint Carlo, who gained the moniker "God's influencer", is the first saint to have grown up in the internet age.

"He had a message; he had work to do even though he was so young, and he felt that he needed to do that work in the [best] way he knew how," Dr Pizzey says.

While digital evangelism is not new, Dr Pizzey says Saint Carlo's youth and devotion to his cause were "quite unusual".

"With his work through the internet, reaching out to people from all over the world, you could say he was actually one of the most extraordinary pilgrims in [how] far he travelled," she says.

"[That's] central to the idea of pilgrimage: to go out and to encounter people."

Saint Carlo's online mission gained praise from Pope Francis, who had previously spoken about the need for technology to be in service of "human dignity".

Professor Pierce says the late pope appreciated Saint Carlo's message: "that [technology and faith] don't need to be distinct, as long as your heart's in the right place".