The famous apparitions of the Virgin Mary to the children of Fatima took place during the First World War, in the summer of 1917. The inhabitants of this tiny village in the diocese of Leiria (Portugal) were mostly poor people, many of them small farmers who went out by day to tend their fields and animals. Children traditionally were assigned the task of herding the sheep.
The three children who received the apparitions had been brought up in an atmosphere of genuine piety: Lucia dos Santos (ten years old) and her two younger cousins, Francisco and Jacinta. Together they tended the sheep and, with Lucy in charge, would often pray the Rosary kneeling in the open. In the summer of 1916 an Angel appeared to them several times and taught them a prayer to the Blessed Trinity.
On Sunday, May 13, 1917, toward noon, a flash of lightning drew the attention of the children, and they saw a brilliant figure appearing over the trees of the Cova da Iria. The "Lady" asked them to pray for the conversion of sinners and an end to the war, and to come back every month, on the 13th.
Further apparitions took place on June 13 and July 13. On August 13 the children were prevented by local authorities from going to the Cova da Iria, but they saw the apparition on the 19th. On September 13 the Lady requested recitation of the Rosary for an end to the war. Finally, on October 13, the "Lady" identified herself as "Our Lady of the Rosary" and again called for prayer and penitence.
On that day a celestial phenomenon also took place: the sun seemed to tumble from the sky and crash toward earth. The children had been forewarned of it as early as May 13, the first apparition. The large crowd (estimated at 30,000 by reporters) that had gathered around the children saw the phenomenon and came away astounded.
Official recognition of the "visions" which the children had at the Cova da Iria came on October 13, 1930, when the bishop of Leiria - after long inquiry - authorized the cult of Our Lady of the Rosary at the site. The two younger children had died: Francisco (who saw the apparition but did not hear the words) on April 4, 1919, and his sister Jacinta on February 20, 1920. Sister Lucia died on February 13 at her Carmelite convent in Coimbra, Portugal, after a long illness.
~from Dictionary of Mary, Catholic Book Publishing Company.
image via Cardinal Sean's blog