"Martyrs must have suffered death for Christ's sake and for the Gospel, because they are priests, women religious or secular Christians who professed and practiced the faith without violence," said the bishop, whose letter was published on his diocese's website.

At a mid-March conference preparing for the plenary, Cardinal Ricardo Blazquez Perez, president of the Spanish bishops' conference, said: "Martyrdom is like a test which unequivocally proves the quality of a Christian, in which spiritual and moral stature reaches a supreme height. ... Martyrs question the courage and humility of our religious belief. They reject worldly accommodations and compromises and show we can submit to the highest demands of faith."

Other martyrs include Father Jose Alvarez-Benavides de la Torre, who catalogued the Almeria Diocese's archives as cathedral dean and was shot and thrown down a well at Cantavieja after being accused of hiding money and weapons.

The oldest martyr, Passionist Father Luis Eduardo Lopez Gascon, 81, who had served as a missionary in Mexico, was seized at his Adra parish when Republicans ransacked his rectory and forced him to swallow his rosary. He died in prison.

The youngest, Luis Quintas Duran, 18, was water-boarded and shot through the neck at the same prison after refusing to renounce his faith. His 14-year-old brother, Don Mario, was forced to dig his grave. In the 1950s, the militiaman who shot Luis Quintas Duran visited the family to ask forgiveness.

Their elder brother, Jose Quintas Duran, a medical student, was buried alive after being forced to dig his own grave. He, too, will be beatified.

More than 6,800 Catholic clergy and religious order members, 12 percent of the Spanish total, were killed during the Civil War after a left-wing Popular Front government launched an aggressive anti-clerical campaign, which included the desecration and torching of thousands of churches, convents and monasteries.

The March 25 beatifications will be the 22nd such ceremony conducted since 1987 for Civil War martyrs, 1,584 of whom have previously been declared blessed and 11 canonized.