Francisco and Jacinta Marto

Francisco de Jesus Marto (11 June 1908 – 4 April 1919) and Jacinta de Jesus Marto (5 March 1910 – 20 February 1920) were siblings from Aljustrel, a small hamlet near Fátima, Portugal, who, with their cousin Lúcia dos Santos (1907–2005), reportedly witnessed three apparitions of the Angel of Peace in 1916, and several apparitions of the Blessed Virgin Mary at Cova da Iria in 1917.

The title Our Lady of Fátima was given to the Virgin Mary as a result, and the Sanctuary of Fátima became a major centre of world Christian pilgrimage.

The brother and sister, who tended to their families' sheep with their cousin Lúcia in the fields of Fátima, Portugal, reported seeing several apparitions of an angel in 1916.

Lúcia later recorded the words of several prayers she said they learned from this angel.

Sister Lúcia wrote in her memoirs that she and her cousins saw the first apparition of Mary on 13 May 1917.

At the time of the apparition, Francisco was 8 years old, and Jacinta was 7.

During the first apparition, the children said Mary asked them to pray the Rosary and to make sacrifices, offering them for the conversion of sinners.

She also asked them to return to that spot on the thirteenth of each month for the next six months.

The siblings were victims of the great 1918 influenza epidemic that swept through Europe that year.

In October 1918, Jacinta told Lúcia that Mary had appeared to her and promised to take them to heaven soon.

Both lingered for many months, insisting on walking to church to make Eucharistic devotions and prostrating themselves to pray for hours, kneeling with their heads on the ground as they said the angel had instructed them to do.

Francisco declined hospital treatment on 3 April 1919, and died at home the next day.

In an attempt to save her life, which she insisted was futile, Jacinta was moved to Ourém Hospital.

Her condition steadily worsened and, in an attempt to transfer her to the children's hospital in Lisbon, Queen Stephanie's Hospital (which at the time only allowed for children from the city to be treated there), she was moved first to the care of the small Orphanage of Our Lady of Miracles, in the Lisbon neighbourhood of Estrela.

She developed purulent pleurisy and endured an operation in which two of her ribs were removed.

Because of the condition of her heart, she could not be fully anesthetized, and suffered terrible pain, which she said would help to convert many sinners.

On 19 February 1920, Jacinta asked the hospital chaplain who heard her confession to bring her Holy Communion and administer Extreme Unction because she was going to die "the next night".

He told her that her condition was not that serious and that he would return the next day.

The next day Jacinta was dead; she had died, as she had often said she would, alone.

In 1920, shortly before her death at age nine, Jacinta Marto reportedly discussed the Alliance of the Hearts of Jesus and Mary with a then 12-year-old Lúcia dos Santos and said:

When you are to say this, don't go and hide.

Tell everybody that God grants us graces through the Immaculate Heart of Mary; that people are to ask her for them; and that the Heart of Jesus wants the Immaculate Heart of Mary to be venerated at his side.

Tell them also to pray to the Immaculate Heart of Mary for peace, since God entrusted it to her.

Jacinta and Francisco are both buried at the Basilica of Our Lady of the Rosary of Fátima.

Exhumed in 1935, Jacinta's face was found to be incorrupt; Francisco's had decomposed.

In 1937 Pope Pius XI decided that causes for minors should not be accepted as they could not fully understand heroic virtue or practice it repeatedly, both of which are essential for canonization.

The cause for the siblings' canonization began in 1946.

By 1951, when she was again exhumed for her reburial in the Basilica, Jacinta had begun to decompose also.

The two Marto children were solemnly canonized by Pope Francis at the Sanctuary of Our Lady of Fátima, in Portugal, on 13 May 2017, the centennial of the first Apparition of Our Lady of Fátima.

They are the youngest Catholic saints, with Jacinta being the youngest saint who did not die a martyr.

The youngest children of Manuel and Olimpia Marto, Francisco and Jacinta were typical of Portuguese village children of that time.

They were illiterate.

According to the memoirs of their cousin Sister Lúcia, Francisco had a placid disposition, was somewhat musically inclined, and liked to be by himself to think.

Jacinta was affectionate with a sweet singing voice and a gift for dancing.

Following their experiences, their fundamental personalities remained the same.

Francisco preferred to pray alone, saying that this would "console Jesus for the sins of the world".

Jacinta said she was deeply affected by a terrifying vision of Hell shown to the children at the third apparition, and deeply convinced of the need to save sinners through penance and sacrifice as the Virgin had told the children to do.

All three children, but particularly Francisco and Jacinta, practiced stringent self-mortifications to this end.

The Congregation for the Causes of Saints, in the report that confirmed Jacinta as beatified, observed that she seemed to have an "insatiable hunger for immolation."

By this the Congregation was referring to immolation as offering in sacrifice.