Lúcia de Jesus Rosa dos Santos was the eldest of the three Fátima seers, with her cousins Francisco and Jacinta Marto (see their joint entry). She was ten when the six apparitions of the Virgin Mary came to the Cova da Iria between May and October 1917, and it was to her that Our Lady spoke; on 13 June she was told that Francisco and Jacinta would be taken to heaven soon but that she would remain in the world for a long time, to make the Immaculate Heart known and loved — which proved the case. She was present for the Miracle of the Sun on 13 October 1917, and she alone lived to be questioned about it for the next eighty-eight years.
She went to school with the Sisters of Saint Dorothy at Vilar, in Porto, from 1921, entered the congregation, and made her vows in 1928. The two further apparitions that completed the Fátima message came to her alone in the Dorothean houses of Spain: at Pontevedra on 10 December 1925, the request for the Communion of reparation on five First Saturdays; at Tuy on 13 June 1929, the request that the Pope, in union with the bishops of the world, consecrate Russia to the Immaculate Heart. At the request of her bishop she wrote her four Memoirs between 1935 and 1941 — the only first-hand account of the apparitions and the first two parts of the secret — and in January 1944 wrote down the third part and sealed it. On 12 August 1946 she told John Haffert what Our Lady asked of ordinary people, and her answer became the Blue Army pledge.
With the permission of Pius XII she entered the Discalced Carmel of Saint Teresa at Coimbra on 25 March 1948 as Sister Maria Lúcia of Jesus and the Immaculate Heart, and lived there in enclosure for fifty-seven years. From the Carmel she wrote, on 8 November 1989, that John Paul II's consecration of 25 March 1984 had been done 'just as Our Lady asked' — the letter the Holy See published in 2000 as settling the question. John Paul II met her at Fátima in 1982, 1991 and 2000, the last time at the beatification of her cousins, when the publication of the third secret was announced; the text was published on 26 June 2000. She died at Coimbra on 13 February 2005 at ninety-seven. Her cause was opened three years later, and on 22 June 2023 Francis declared her Venerable.