An Italian teenager dubbed “God’s Influencer” for his efforts to spread the Catholic faith online will become the first millennial saint Sunday at a canonization attended by thousands of pilgrims.

Computer whiz Carlo Acutis, who died of leukemia in 2006 at the age of 15, will be raised to sainthood by Pope Leo XIV in a solemn ceremony in St. Peter’s Square at the Vatican.

The teenager’s body, dressed in jeans and a pair of Nike trainers, lies in a glass-walled tomb in Assisi, visited by hundreds of thousands of people a year.

His canonization, initially scheduled for April but postponed after Pope Francis’s death, will be watched by the faithful on giant screens in Assisi, a medieval city and pilgrimage site in the central Italian region of Umbria.

Acutis, born in London in 1991, had an ardent faith, though his parents were not particularly devout.

He grew up in the northern city of Milan, where he attended mass daily and had a reputation for kindness to bullied children and homeless people, bringing the latter food and sleeping bags.

A fan of computer games, Acutis taught himself basic coding and used it to document miracles and other elements of the Catholic faith online.

The Vatican has credited two miracles to Acutis since his death—a necessary step for sainthood.

The first was the healing of a Brazilian child suffering from a rare pancreatic malformation; the second the recovery of a Costa Rican student seriously injured in an accident.

In both cases, relatives had prayed for help from the teenager, who was beatified in 2020 by Pope Francis.

Over 800 people will be travelling to Rome on a special train from Assisi for the canonization of the so-called “cyber-apostle.”

Canonization is a long and meticulous process, involving an investigation by the Vatican and specialists who assess whether the obligatory miracles had taken place.

Final approval rests with the pope.

Mountaineer also held up

Italian Pier Giorgio Frassati, a mountaineering enthusiast who died in 1925 and was known for his social and spiritual commitment, will also be made a saint on Sunday.

His casket is inscribed with the words “Verso l’alto” (“To the heights”), a phrase he wrote on a photograph taken of him looking up to the summit while mountaineering.

An engineering student who made it his mission to serve the poor and sick of his city, he was held up by the Church as a model of charity after his death from polio at the age of 24.

He was beatified by Pope John Paul II in 1990.

The Vatican recognized the necessary second miracle to put him on the path to sainthood in 2024, with the unexplained healing of a young American man in a coma.

Sunday’s canonization ceremony will be Pope Leo’s first since his election in May.

It falls during the Jubilee, a Catholic Holy Year which has already drawn over 24 million people to Rome, according to the Vatican.