ROME — Pope Francis on Thursday officially recognized a miracle attributed to the intercession of a young brother and sister who said, 100 years ago, that the Virgin Mary had appeared to them in the Portuguese village of Fátima.

The approval of the miracle was the final step needed before the siblings, Jacinta and Francisco Marto, could be made saints. By signing the decree, the pope increased the likelihood that he could canonize the two when he visits the Fátima shrine in May, 100 years to the day that the children said that a vision of Mary had appeared to them for the first time. Officially, no date has been set for the canonization ceremony.

The Marto children and their cousin Lucia de Jesus dos Santos said they had seen the apparitions six times between May 13, 1917, and Oct. 13, 1917, when Jacinta was 7, Francisco was 9 and Lucia was 10.

By the time of the last apparition — in 1917 — 50,000 to 70,000 people had gathered to pray with the children, according to the website of the Shrine of Fátima.