VATICAN CITY - Two 20th-century leaders of the Catholic Church will be declared saints, Pope Francis decided on Friday, as the Vatican announced the forthcoming canonization of Popes John XXIII and John Paul II.

Francis took the decision after recognizing that John Paul II had been responsible for a second miracle after his death, while he decided to waive the second-miracle requirement - usual in sainthood causes - for John XXIII.

The canonization of the two pontiffs will likely take place "before the end of the year," said the Rev. Federico Lombardi, a Vatican spokesman. The precise date is expected to be set by a consistory of cardinals, due to be called by the pope.

John XXIII, the Italian-born Angelo Roncalli, served from 1958 to 1963 and led the Catholic Church toward major reforms by opening the Second Vatican Council in 1962. It concluded three years later under his successor, Paul VI.

"We all know the virtues and the personality of Pope Roncalli. There is no need to explain the motives of his sainthood," Lombardi told reporters.

The Polish-born Karol Wojtyla, whose papacy under the name of John Paul II lasted from 1978 to 2005, is remembered for his charisma and his role in bringing down communist rule in Eastern Europe, starting with his home country.

"The papal decision gives the church in Poland new hope and profound joy that we will be able to enjoy such a rapid canonization," said Wojciech Polak, secretary general of the Polish Episcopal Conference.

John Paul II's second certified miracle was the curing of a brain aneurysm in a Costa Rican woman, the man in charge of steering the canonization process, Monsignor Slawomir Oder, told Vatican Radio. That added to a nun's healing from Parkinson's disease two months after the pontiff's death.

John Paul II's rise to sainthood has been one of the fastest in modern times. Crowds chanted "santo subito" (saint now) at his funeral, and his successor, Benedict XVI, immediately started the process, waiving the normal five-year wait after a candidate's death.

However, some have criticized the move, pointing to Wojtyla's failure to address sex-abuse and financial scandals within the church hierarchy.

John XXIII - who is known in Italy as the "papa buono" (the good pope) - is less controversial. He was beatified by John Paul II in 2000, after he was credited with the 1966 curing of an Italian nun from serious stomach bleeding and infection.

Francis recognized several other miracles and martyrdoms on Friday, allowing for the beatification of Spanish bishop Alvaro Del Portillo, the former head of Catholic conservative group Opus Dei, and of several priests killed during the Spanish civil war.

The announcement came on a remarkable day melding papacies past and present: It opened with Francis and Pope Emeritus Benedict XVI attending their first Vatican ceremony together, sitting side-by-side on matching papal chairs for the unveiling of a statue in the Vatican gardens. It continued with the publication of Francis' first encyclical, a meditation on faith that was largely written by Benedict before he retired but was signed by Francis. And it climaxed with Francis' decision to canonize two other predecessors.

The Rev. Thomas Reese, a Vatican analyst, said the decision to canonize both popes was a "brilliant move to unify the church," given that each pope has his own admirers and critics.

The Associated Press contributed to this report.