Mother Teresa of Calcutta, a Nobel peace laureate known as the "saint of the gutters" during her lifetime, will be made a saint of the Catholic Church on Sunday.
More than 100,000 pilgrims are expected to attend a service led by Pope Francis in St. Peter's Square at the Vatican to honour the tiny nun who worked among the world's neediest in the slums of the Indian city now known as Kolkata.
Her legacy fits neatly with Francis's vision of a poor church that strives to serve the poor, and the ceremony will be a highlight of his Holy Year of Mercy which runs until November 8.
Mother Teresa and her Missionaries of Charity (MoC) order have been criticised both during her life and since her death in 1997, but many Catholics revere her as a model of compassion.
Thousands attended a papal audience on Saturday in the Vatican, where a large canvas of the late nun in her blue-hemmed white robes hung from St Peter's basilica.
"Her testimony makes us reflect and transform...and make a better world," Brazilian priest Carlos Jose Nacimento said.
Critics say she did little to alleviate the pain of the terminally ill and nothing to tackle the root causes of poverty. Atheist writer Christopher Hitchens made a documentary about her called "Hell's Angel".
She was also accused of trying to convert the destitute in predominantly-Hindu India to Christianity, a charge her mission has repeatedly denied.
But Pope John Paul II, who met her often, had no doubt about her eligibility for sainthood, and put her on a fast track to elevation two years after her death instead of the usual five.
