Our Lady of Fatima, kept on 13 May, commemorates the apparitions reported in 1917 by three shepherd children, Lucia dos Santos and her cousins Francisco and Jacinta Marto, at Fatima in Portugal, over six months and drawing large crowds, culminating in the reported "miracle of the sun" witnessed by a crowd in October. The messages, centred on prayer, penance and the rosary, and on a call to consecrate Russia, gave the devotion a strongly twentieth-century and political cast.
The "three secrets of Fatima", written down by Lucia years later, became one of the most discussed items in modern Catholic piety: a vision of hell, a prophecy read against the rise of Soviet communism and a coming war, and a third part withheld until the Vatican published it in 2000, interpreting it in connection with the 1981 attempt on the life of John Paul II. The apparitions and their political reading have been contested inside and outside the church, and historians treat the development of the secrets and their disclosure as a case study in how a devotion is shaped over decades. The shrine is a major pilgrimage centre and the day a national observance in Portugal.