The woman the world came to know as Mother Teresa of Calcutta was called a lot of things in her lifetime.

She was the “Saint of the Gutters” and an “Angel of Mercy.” But also a “religious imperialist” and, in the words of British author Christopher Hitchens, “a fanatic, a fundamentalist and a fraud.”

For all the eloquence of her critics, she was always far more revered than reviled.

The celebrated nun was proclaimed a saint on Sunday. Pope Francis presided over a solemn canonization mass in the presence of 100,000 pilgrims and with a giant haloed portrait of Teresa smiling down from St. Peter‘s Basilica.

The sainthood ceremony, for which the Vatican could easily have issued twice as many tickets, came one day short of the 19th anniversary of Teresa’s death, at 87, in the Indian city where she spent her adult life, first teaching, then tending to the dying poor.

Millions acclaimed her as an icon of Christian charity and a global symbol of anti-materialism and worthwhile self-sacrifice.

On her death in 1997, Britain‘s Queen Elizabeth II predicted Teresa would “continue to live on in the hearts of all those who have been touched by her selfless love.”

Since then however it has become apparent that the private Teresa was a more complex personality. The austere persona she displayed to the world with her gaunt, masculine face, masked a lighter, albeit troubled, soul.

For long periods, she was plagued by doubts about the faith that drove her mission to provide comfort to the dying.

“There is so much contradiction in my soul,” she wrote to the Bishop of Calcutta in a posthumously published letter dating from 1957. “Heaven means nothing to me, it looks like an empty place.”

Two years later, she wrote to a priest friend saying: “If I ever become a saint, I will surely be one of darkness; I will continually be absent from heaven -- to light the light of those in darkness on earth.”

The saintly tag became official thanks to a fast-track canonization process that reached its conclusion on the eve of the anniversary of her death.

Baptized Agnes Gonxha Bojaxhiu, Teresa was born into a Kosovar Albanian family in 1910 in Skopje, then part of the Ottoman empire and now the capital of Macedonia.

Her father, a businessman who was involved in the region’s byzantine politics, died when she was eight.

By the time she was 12, according to biographers, Agnes was already a regular visitor to Catholic shrines and knew that she wanted to dedicate her life to missionary work.

At 18 she enrolled in an Irish order, the Sisters of Loreto, spending a brief period in Ireland learning English before her departure for India in 1929.

There she spent two decades teaching geography to the children of well-to-do families before founding her own order in 1950.

In 1979, her work in the Calcutta slums was rewarded with the Nobel peace prize. In her acceptance speech she made a fervent defense of her approach to helping the poor, which was by then coming under increasing critical scrutiny.

To those who said birth control was vital to combatting poverty, she replied that abortion was “direct murder by the mother.”

To those who said her Order should promote development, she replied that she was a missionary, not a social worker.

“We may be doing social work in the eyes of the people, but we are really contemplatives in the heart of the world,” she said. “For we are touching the Body of Christ 24 hours.”

Teresa could come across as an ascetic figure and as a strict task-mistress to those under her. “She spoke her mind,” Pope Francis recalled in 2014. “I would have been a little bit scared had she been my Mother Superior.”

Those who knew her best however paint a different picture of the chocolate and ice cream-loving nun.

Father Brian Kolodiejchuk, a member of her Order who promoted her sainthood cause within the Vatican, recalls a maternal, easily-amused character who could sometimes be found bent over in laughter while discussing the day‘s events with fellow nuns.

“She could be very demanding and at the same time, especially when a mistake was made, she could be very loving and tender and understanding as well,” he told AFP.

“You felt that she was a mother,” he said. “She was not very good at telling jokes but she had a sense of humor and could really find the funny aspects in ... daily life.”(AFP)