Pope Leo XIV canonized Carlo Acutis on Sunday, declaring the Italian teenager who died of leukemia at 15 a saint before tens of thousands of cheering worshippers.
The Catholic Church regards Acutis as a model young Christian who dedicated his life to the service of God. Alongside him, Pier Giorgio Frassati, another Italian who died young, in 1925, was also elevated to sainthood.
For Pope Leo, the head of the world's 1.4 billion Catholics, it is the first canonization since his election four months ago.
In Latin, he proclaimed, "We enrol the blessed Pier Giorgio Frassati and Carlo Acutis in the list of saints and decree that they be venerated as saints throughout the Church." Relics of the two were then brought to the altar.
Two large portraits of the new saints were hanging on the front of St Peter's Basilica.
Among the participants of the service were Acutis' parents and his two siblings.
The teenager died in 2006, within a few days after the onset of his illness.
From the perspective of the Catholic Church, he had led an exemplary life for a young Christian up to that point. Furthermore, it is claimed that he performed two miracles after his death.
Acutis is referred to by the Vatican as a "cyber apostle" and "God's influencer" because he also promoted his faith on the internet.
During his lifetime, he also helped priests set up websites for their parishes and built an online database of religious miracles, which is still accessible today.
The Church aims to become more attractive to young people through the canonizations. However, there is also criticism. A cult of personality has developed around the boy, whose body is displayed in a church in the small Italian town of Assisi.
Last year, more than 1 million people visited the church. Numerous souvenirs of the teenager are sold in the souvenir shops of his hometown of Saint Francis. Relics of him have also been exhibited outside Italy.
Frassati (1901-25) was the other Italian who died young who was canonized on Sunday. He is said to have been particularly committed to helping the poor and marginalized.
Both initiatives date back to the predecessor of the first pope from the United States, the Argentinian Francis, who died at Easter.
Overall, the Catholic Church has more than 10,000 saints, starting with the Virgin Mary and almost all the apostles.
Beatifications and canonizations follow a complicated, multi-stage process. The lives of the candidates are thoroughly examined. In the past, this began no sooner than 50 years after death. For Acutis, the process took less than 20 years.
Typically, it is required that miracles can be attributed to a potential saint. In the case of the teenager, the Vatican considers two healings in Brazil and Italy to be valid.
