Pope Francis proclaimed his predecessors John XXIII and John Paul II saints in front of more than half a million pilgrims on Sunday, hailing both as courageous men who withstood the tragedies of the 20th century.

Cheers and applause rang out across St. Peter's Square after the historic double papal canonization as many in the crowd fixed their gaze on huge tapestries of the two popes on the facade of the basilica behind Francis.

"We declare and define Blessed John XXIII and John Paul II to be saints and we enrol them among the saints, decreeing that they are to be venerated as such by the whole Church," Francis said in his formal proclamation in Latin.