Mother Teresa Credit: Tim Graham/Getty Images

Nearly two decades after her death, Mother Teresa will be declared a saint under the Roman Catholic Church, the Vatican announced on Friday, December 18.

The Vatican confirmed to NBC News in its statement that Pope Francis — who celebrated his 79th birthday on Thursday, December 17 — approved a decree that Mother Teresa had performed a second miracle.

Under the Catholic Church, the declaration of sainthood depends on the execution of two miracles. In 2003, Mother Teresa was beatified as "Blessed Teresa of Calcutta" after healing a tumor. Her second miracle took place in 2008, with the healing of a man in Brazil who was suffering from a brain infection.

The man was supposedly in a coma and about to undergo an emergency operation when the surgeon "found the patient inexplicably awake and without pain," according to a statement from Father Brian Kolodiejchiuk to NBC. "The patient's wife continuously sought the intercession of the Blessed Mother Teresa for her husband," added Kolodiejchiuk, who spearheaded Mother Teresa's canonization case.

The Vatican later said that at the time of the man's surgery, his wife was praying for Mother Teresa's intercession alongside her pastor.

Mother Teresa is best known for her mission work and devotion to the poor in the Indian city of Kolkata. In 1979, she won the Nobel Peace Prize for her charitable spirit and inspiring actions. She died at 87 in September 1997.

Multiple Italian newspapers and outlets have speculated that the late nun will be canonized in September 2016, which will overlap with two significant events: Pope Francis' Holy Year of Mercy and the 19th anniversary of her death.

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