July 13, 1917
Our Lady appeared to Lucia Santos, Francisco Marto and Jacinta Marto a third time. She showed them hell where the souls of poor sinners go. She revealed God's plan to save the people from the fire of hell. Our Lady asked the children to offer themselves to God and
sacrifice themself for sinners. Our Lady said, that She will come later to ask for the Consecration of Russia to Her Immaculate Heart, and the Communion of Reparation on the First Saturdays (the Devotion of Reparation). All this became known as the Secret of Fatima.
August 31, 1941
Sister Lucia wrote the final words of Third Memoir on August 31, 1941. For the first time she revealed the first two parts of the Secret: one about hell and a second one about the Immaculate Heart of Mary. While writing her Third Memoir, Sister Lucia makes it clear that she will not reveal the third part of the Secret.
December 8, 1941
Sister Lucia sent her writings of Fourth Memoir to the Bishop da Silva. She had made a point of repeating the two parts of the Great Secret, both times (in the Third Memoir and in the Fourth Memoir)
exactly in the same terms, except that in the last writing she added the phrase from the Third Secret:
“In Portugal, the dogma of faith will always be preserved, etc…”
Bishop da Silva gives her the formal order to write the Secret. Sister Lucia, mysteriously prevented, is unable to fulfill her obedience.
January 2, 1944
The apparition of Our Lady in Tuy, Spain. The Mother of God has strengthened Lucia and confirmed to her that it is indeed God’s will that she should write the words of the final Third Secret and give it to Church hierarhy.
From 1946 to 1960
Numerous testimonies stating that the Third Secret «will have to be read to the world in 1960», «because the Holy Virgin wishes it so».
September 2, 1952
Father Schweigl, with permission of the Pope Pius XII, questions Sister Lucia on the Third Secret. Later he will tell to colleague that the Secret consists of two parts.