Pope Francis created five new saints on Sunday, including Britain's Cardinal John Henry Newman -- one of the Catholic Church's most renowned converts -- and a nun dubbed the "Mother Teresa of Brazil".
Heads of state from across the world attended the canonisation ceremony, which also raised a Swiss laywoman plus two other nuns -- an Indian and an Italian -- to the highest position within the Church.
"Today we give thanks to the Lord for our new Saints," the pope told the faithful on Saint Peter's Square.
"They walked by faith and now we invoke their intercession."
Prince Charles, future head of the Church of England, led the British delegation honouring Newman, a 19th-century Anglican theologian who went on to become one of the Catholic Church's leading thinkers.
Francis quoted Newman describing "the holiness of ordinary life" in which, "the Christian is cheerful, easy, kind, gentle, courteous, candid, unassuming; has no pretence... with so little that is unusual... that he may easily be taken at first sight for an ordinary man."
Born in 1801, Newman attempted to "renew" the Anglican Church, before becoming convinced that Catholicism was the only true faith and converting aged 44, rising through the hierarchy to become a cardinal.
Giant portraits of the new saints were hung from Saint Peter's Basilica for the ceremony which attracted tens of thousands of pilgrims.
The pope noted that three of the new saints were religious women, showing "that the consecrated life is a journey of love at the existential peripheries of the world".
But the fourth, Marguerite Bays, was a seamstress, a laywoman from Switzerland known for bearing the stigmata -- wounds corresponding to the injuries Christ suffered on the cross.
"She speaks to us of the power of simple prayer, enduring patience and silent self-giving," Francis said.
Born in 1815, the second of seven children, Bays showed an intense faith from very early on, often breaking off from playing with other village youngsters in order to pray quietly, according to the Vatican.
Despite suggestions she should become a nun, she instead began an apprenticeship as a seamstress aged 15.
Bays underwent surgery for bowel cancer in 1853, and prayed to the Virgin Mary to heal her, offering to swap her disease for the pains experienced by Jesus. The Church says she was cured but given the stigmata in exchange.
Every Friday, she would be immobilised in "ecstasy" as she relived the suffering in body and mind, it says.
Most new saints must have two "miracles" to their names -- usually scientifically inexplicable healings, attributed to prayers.
Newman is credited with curing an American man from Boston with a debilitating spinal disorder, who claimed in 2001 he could suddenly walk again after praying to the British cardinal.
His second "miracle" -- the inexplicable healing of a woman with a "life-threatening pregnancy" -- was approved this year.
Bays was canonised alongside Brazilian Sister Dulce Lopes Pontes, who was a member of the Missionary Sisters of the Immaculate Conception and considered a "mother of the poor".
Born in 1914 into an upper middle-class family in Salvador, she started a health clinic for poor workers and opened a school, a hospital, and an orphanage, as well as care centres for the elderly and disabled.
Sister Dulce, dubbed the "good angel of Bahia", was nominated for the Nobel Peace Prize in 1988.
She was visited in hospital the year before her death by Pope John Paul II, who called her work "an example for humanity".
Tens of thousands of people attended her funeral in 1992.