The devotion to Our Lady of Fatima is based on the belief of the apparitions of the Virgin to three shepherd children – Lucia (beatified in 2008), St. Francis Marto and St. Jacinta Marto (canonized in 2017) – in the place of Cova da Iria, now known as the Altar of the World. The six apparitions took place monthly between May 13 and October 13, 1917, and the "Lady" called for prayer, penance, and conversion.
The statement of the "little shepherds" determined the iconography of Our Lady of the Rosary of Fatima: over a cloud and dressed in white, with a rosary suspended over her hands arranged in prayer.