Mother Teresa declared a saint by Pope Francis

 Mother Teresa, a Catholic nun who devoted her life to helping India's poor, has been declared a saint in a canonization Mass held by Pope Francis in the Vatican.

Pope Francis delivered the formula for the canonization of the Albanian-born nun -- known as the "saint of the gutters" -- before huge crowds of pilgrims gathered in St. Peter's Square in Vatican City on Sunday morning.

Applause broke out before he completed the formula of canonization, in which he declared "Blessed Teresa of Calcutta to be a saint."

India renamed the city of Calcutta to Kolkata in 2001 to match the Bengali pronunciation. But the church uses the spelling of Calcutta in its references to Mother Teresa.

Speaking in Latin, Francis said that "after due deliberation and frequent prayer for divine assistance, and having sought the counsel of many of our brother bishops, we declare and define Blessed Teresa of Calcutta to be a saint, and we enrol her among the saints, decreeing that she is to be venerated as such by the whole church."

Catholics -- including hundreds of blue- and white-robed nuns from the Missionaries of Charity sisterhood founded by Mother Teresa -- had gathered from around the world to attend the canonization of the church's newest saint, just 19 years after her death.

A huge portrait of Mother Teresa, whom the church credits with having performed two miraculous cures of the sick, hung from St. Peter's Basilica during the colorful ceremony.

Francis: 'May she be your model of holiness'

Pope Francis then delivered a homily, in which he praised Mother Teresa -- "this emblematic figure of womanhood and of consecrated life" -- for her charitable work.

"Mother Teresa, in all aspects of her life, was a generous dispenser of divine mercy, making herself available for everyone through her welcome and defense of human life, those unborn and those abandoned and discarded," he said.

"She bowed down before those who were spent, left to die on the side of the road, seeing in them their God-given dignity. She made her voice heard before the powers of this world, so that they might recognize their guilt for the crime of poverty they created."