Pope Francis has given final approval to the canonization of two of his predecessors, John Paul II and John XXIII, the Vatican said Friday.

The pontiff recognized the validity of a second miracle attributed to John Paul, a prerequisite for sainthood.

In the case of John XXIII, however, Francis invoked his authority to waive the requirement of a second miracle and allow the canonization to proceed without it.

Angelo Roncalli (1881-1963) became pope in 1958 and wrought something akin to a revolution in the Roman Catholic Church through the mechanism of the Second Vatican Council.

The first-ever Polish pontiff, Karol Wojtyla (1920-2005), was a indefatgiable traveler and preacher whose long pontificate - nearly 27 years - gave him the chance to leave a strong imprint on the institutions of the church.

John Paul I beatified John XXIII in 2000 and was in turn beatified by his successor, Pope Benedict XVI, in 2011.

No date has been set for the canonization ceremony, but Vatican spokesman said it will probably come toward the end of the year. EFE