VATICAN CITY -- Pope Francis said Monday that he would canonize two of his most influential predecessors, John Paul II and John XXIII, on the same day next spring, a highly unusual move that was taken as an effort to promote unity within the Roman Catholic Church.
The two popes, who have disparate followings among reformers and conservatives within the church, will be declared saints on April 27, Francis said during a meeting with cardinals at the Vatican. Each achieved considerable international stature: John Paul II for encouraging the fall of Communism in his native Poland and across Eastern Europe, and John XXIII for assembling the liberalizing Second Vatican Council, which ran from 1962 to 1965.
"To celebrate them together is a sign of appreciation of the holiness of two popes who paid witness to our time," the Vatican spokesman, the Rev. Federico Lombardi, said during a news conference on Monday.
The pope announced in July that he would canonize the two men but did not set a date, and there were initial indications that he would act this year. Father Lombardi said April 27, the first Sunday after Easter, would be "a good date for pilgrims who might already be in Rome." The date is also known as Divine Mercy Sunday. John Paul II promoted devotion to the Feast of the Divine Mercy and was beatified -- a step toward canonization -- on that day in 2011, Father Lombardi noted.
Candidates for sainthood usually have two miracles attributed to them. But Francis approved the canonization of John XXIII with only one -- the curing of an ailing woman -- which Father Lombardi said in July was a result of eagerness to honor "the great pope of the Second Vatican Council."
On Monday, he said the canonization should be seen "in the context of the 50th anniversary of the Second Vatican Council, and the universally heartfelt fame that surrounds John XXIII."
Alberto Melloni, the director of the John XXIII Center in Bologna, Italy, said Francis was holding to the pattern of promoting John, popular among liberals, by pairing him with a pope more popular among conservatives. Mr. Melloni said soon after John's death in 1963, a campaign to have him acclaimed a saint during the Vatican Council was countered by the conservative wing of the church, which soon after opened the canonization process for Pius XII, a staunch anti-Communist who led the church during World War II.
"John XXIII is the father of Vatican II, and to canonize him is to canonize the council as such and its intention of renewal and unity," Mr. Melloni said. "But the Vatican is also taking into consideration the tension and sometimes harsh debate that arose around the council, and so they have remained faithful to the idea of linking John XXIII with someone else." Pairing the popes "also balances a very long canonization process with an incredibly accelerated procedure," he added. John Paul II will become a saint only nine years after his death.
On Monday, Father Lombardi said that Benedict XVI, the pope emeritus, might join Francis in the canonization ceremony.
"There is no reason -- either doctrinal or institutional -- that he couldn't participate in the public ceremony," he said, responding to news reports from Poland that Benedict would be present.
Benedict stepped down in February and has been living in self-imposed isolation in a monastery inside the Vatican walls.
Elisabetta Povoledo reported from Vatican City, and Alan Cowell from London.
This article originally appeared in The New York Times.