May 13, 1917, three children were pasturing their little flock in the Cova da Iria, parish of Fatima, the municipality of Vila Nova de Ourém, today the Diocese of Leiria-Fatima. They were called: Lucia de Jesus, 10, and Francisco and Jacinta Marto, cousins, 9 and 7 years.

Around midday, after praying the Rosary, as was their custom, to entertain a small house built of loose stones at the site where today stands the Basilica. Suddenly, they saw a bright light, thinking it a flash of lightning, they decided to go away, but just below, another flash lit up the place, and on top of a small oak (where now stands the Chapel of the Apparitions), a "Lady more brilliant than the sun", from whose hands hung a white rosary.

The Lady told the three shepherd children had to pray a lot and invited them to return to the Cova da Iria during five consecutive months, 13 days in that hour. The children did so, and the 13th day of June, July, September and October, the Lady appeared to them again and spoke to them in the Cova da Iria. The August 19, the sign was in Valinhos, about 500 meters from Aljustrel, because in 13 days, the children had been taken by the County Administrator to Vila Nova de Ourém.

In the last apparition, on 13 October, in the presence of about 70,000 people, the Lady told them that was the "Lady of the Rosary" and to do a chapel in her honor. After the apparition all present witnessed the miracle promised to the three children in July and September: the sun, resembling a silver disc, could be gazed at without difficulty and, whirling on itself like a wheel of fire, like precipitate on the ground.

Afterwards, when Lucia was a Religious Sister of Saint Dorothy, Our Lady appeared to her again in Spain (10 December 1925 and February 15, 1926, the Convent of Pontevedra, and on the night of 13/14 June 1929 in the Convent of Tuy), requesting the devotion of the five first Saturdays (to pray the Rosary, meditate on the mysteries of the Rosary, confess and receive Holy Communion, in reparation for sins committed against the Immaculate Heart of Mary) and the Consecration of Russia to the Immaculate Heart even . This request has already announced in the Our Lady July 13, 1917.

Years later, Sister Lucia tells us that, between April and October 1916, an angel had appeared to the three seers, three times, twice in the Cabeço and another at the well of the back yard of Lucy, inviting to prayer and penance.

Since 1917, it ceased to come to the Cova da Iria thousands and thousands of pilgrims from around the world, in the first 13 days of each month, after the months of summer vacation and winter, and now increasingly on weekends and day-to-day, an annual amount of five million.