Lucia dos Santos wrote this poem, and it is on page 20 of her book Fatima in Lucia's own words. The following things about Jacinta are also to be found in the book.
Jacinta was born on March 11, 1910; and was baptized on March 19, eight days later. She was the darling daughter of Manuel and Olimpia Marto. These vigilante and protective parents watched their charming and vivacious daughter grow into a saint. "Before the happening of 1917, apart from the ties of relationship that united us, no other particular affection led me to prefer the companionship of Jacinta and Francisco to that of any other child. On the contrary, I sometimes found Jacinta's company quite disagreeable, on account of her oversensitive temperament. The slightest quarrel which arose among the children when at play was enough to send her pouting into a corner- "tethering the donkey" as we used to say. Even the coaxing and caressing that children know so well how to give on such occasions, were still not enough to bring her back to play; she herself had to be allowed to choose the game, and her partner as well. Her heart, however, was well disposed. God had endowed her with a sweet and gentle character which made her at once lovable and attractive. I don't know why, but Jacinta and her brother Francisco had a special liking for me, and almost always came in search of me when they wanted to play."
Lucia's mother graciously allowed the children of the village to play at her house while the parents were working in the fields. At siesta time, Lucia's mother would give her children their catechism lessons all the children were therefore able to learn together. One day some of the children had to be disciplined and Lucia's mother pointed out that sins displease the Child Jesus. Jacinta took this lesson to heart and would stay home in her own yard if the others were misbehaving. She said she did not want to learn any thing that would hurt the Child Jesus.
Jacinta and her brother Francisco were fascinated by the Child Jesus and His presence in the host. They referred to the host as the 'Hidden Jesus". Page 26 "The two children, who ardently desired to receive the "Hidden Jesus", as they called Him, went to ask their mother, and my aunt agreed. But she rarely let them go there, for she said: "The church is a good way from here, and you are very small. In any case, the priest won't give you Holy Communion before you're ten years old."
After the apparitions the children were accumulating so many graces; and their lives centered on doing God's Holy Will. Jacinta seemed to be solely concerned with the one thought of converting sinners and saving souls from going to hell. She followed the directions given to obtain this goal. Page 151- "Pray! Pray very much! The Hearts of Jesus and Mary have designs of mercy on you. Offer prayers and sacrifices constantly to the Most High."
Jacinta began to fast and pray. She was a talented dancer and decided to offer for penance this favorite pastime. She bravely prayed her rosary when imprisoned. She bravely stood her ground when threatened with death. She cried in her jail cell when she thought about her mother, but gallantly offered her suffering in reparation for the sins committed against the Immaculate Heart of Mary. Page 37 - "I am making the offering for all the intentions, because I love them all."
Page 42 " Our Lady came to see us," Jacinta said. "She told us she would come to take Francisco to heaven very soon, and she asked me if I still wanted to convert more sinners. I said I did. She told me I would be going to a hospital where I would suffer a great deal; and that I am to suffer for the conversion of sinners, in reparation for the sins committed against the Immaculate Heart of Mary, and for love of Jesus. I asked if you would go with me. She said you wouldn't, and that is what I find hardest. She said my mother would take me, and then I would have to stay there all alone!" "After this, she was thoughtful for awhile and then added: "If only you could be with me! The hardest part is to go without you. Maybe, the hospital is a big dark house, where you can't see and I'll be there suffering all alone! But never mind! I'll suffer for love of Our Lord, to make reparation to the Immaculate Heart of Mary, for the conversion of sinners and for the Holy Father."
"When the moment arrived for her brother to go to heaven, she confided to him these last messages: "Give all my love to Our Lord and Our Lady, and tell them that I'll suffer as much as they want, for the conversion of sinners and in reparation to the Immaculate Heart of Mary."
"Jacinta suffered keenly when her brother died. She remained a long time buried in thought, and if anyone asked her what she was thinking about, she answered: "About Francisco. I'd give anything to see him again!" Then her eyes brimmed over with tears."
The Immaculate Queen told Jacinta not to be afraid since She Herself would come to take Jacinta to Heaven. When Lucia asked Jacinta what she would do in Heaven, Jacinta replied: "I'm going to love Jesus very much, and the Immaculate Heart of Mary, too. I'm going to pray a lot for you, for sinners, for the Holy Father, for my parents and my brothers and sisters, and for all the people who have asked me to pray for them."
The Immaculate Queen had told Jacinta the day and the hour of her death. So even if she seemed much improved, Jacinta asked for Last Rites. That same night at 10:30 the Immaculate Queen came to take Jacinta to Heaven.
THE CHILDREN OF FATIMA (Great Book)