VATICAN CITY (AP) — Pope Francis has signed off on the miracle needed to make Mother Teresa a saint, giving the nun who cared for the poorest of the poor one of the Catholic Church's highest honors just two decades after her death.

The Vatican said Friday that Francis approved a decree attributing a miracle to Mother Teresa's intercession during an audience with the head of the Vatican's saint-making office on Thursday, his 79th birthday.

No date was set for the canonization, but Italian media have speculated that the ceremony will take place in the first week of September — to coincide with the anniversary of her death, and during Francis' Holy Year of Mercy.

Mother Teresa, a Nobel Peace Prize winner, died on Sept. 5, 1997, aged 87. At the time, her Calcutta, India-based Missionaries of Charity order had nearly 4,000 nuns and ran roughly 600 orphanages, soup kitchens, homeless shelters and clinics around the world.

Mother Teresa, born in Macedonia as Agnes Gonxha Bojaxhiu in 1910, was beatified in 2003 in Rome after the Vatican said an Indian woman's prayers to the nun rid her of an incurable tumor.

The miracle needed for her canonization concerned the inexplicable cure in 2008 of a man in Brazil with multiple brain abscesses who, within a day of being in a coma, was cured, according to a report in Avvenire, the newspaper of the Italian bishops' conference. The Vatican ascertained that his wife's prayers for Mother Teresa's intercession were responsible, the report said.

Francis, whose papacy has been dedicated to ministering to the poor just as Mother Teresa did, is a known fan. During his September 2014 visit to Albania, Francis confided to his interpreter that he was not only impressed by her fortitude, but in some ways feared it.

Francis recounted that he had met Mother Teresa when they attended a 1994 bishop synod at the Vatican together. At the time, he was Archbishop Jorge Mario Bergoglio.

"Bergoglio had Mother Teresa behind him, nearby, and he heard her intervene often with great strength, without letting herself in any way be intimidated by this assembly of bishops," the Vatican spokesman, the Rev. Federico Lombardi, later recounted. "And from that he developed a great esteem for her, as a strong woman, a woman able to give courageous testimony."

But Bergoglio, who has long shown admiration for the women who raised him and taught him, added: "I would have been afraid to have had her as my superior, since she was so tough."