Pope Francis just recognized Mother Teresa’s second miracle. Now she will become a saint.

Mother Teresa, the Catholic nun famous for her work among the poor in Kolkata, India, is going to be made a saint, the Vatican has announced.

The Vatican must recognize two miracles in order to canonize a saint, and Mother Teresa was put on a fast track toward sainthood after her death in 1997. Pope John Paul II recognized the first miracle, required for beatification, in 2003; Pope Francis has now recognized a second.

The miracle, according to the church, is that a Brazilian man whose family prayed to Mother Teresa was miraculously cured of brain tumors in 2008, while he was in a coma and about to enter surgery. The first miracle attributed to Mother Teresa also dealt with the disappearance of a tumor, this one of a woman in India.

Mother Teresa will probably be canonized in September as part of the pope's Jubilee Year of Mercy.

Sainthood for Mother Teresa is hardly a surprise — even in her lifetime, she was called a "living saint" for devoting her life to the poor and to people living in slums. She won the Nobel Peace Prize in 1979.

But after her death, the narrative about her life has become more complicated. Her letters, published in 2003, revealed that she suffered a crisis of faith for decades, which James Martin described in the New York Times as "almost unparalleled in the lives of the saints."

Other critics, most prominently Christopher Hitchens, have questioned her alliances with the rich and unethical, such as Haitian dictator Jean-Claude Duvalier, from whom she raised funds; the conditions in her home for the dying; and her opposition to birth control. Mother Teresa viewed suffering as ennobling, and critics argue she did not do enough to relieve patients' pain.

"She had most of the attributes of sainthood: a dauntingly selfless life, devotion to a higher cause, rude single-mindedness, a thick skin, and a capacity to wring the withers of the rich and powerful," the Economistwrote when she died in 1997.

Go deeper:

• Mother Teresa's speech upon receiving the Nobel Peace Prize includes denunciations of abortion as well as exhortations to help the poor; it's the best place to start for how she saw her own work.