From Quod Anniversarius, the Encyclical Letter of Pope Leo XIII on his Sacerdotal Jubilee, issued on the 1st day of April, 1888:
"5. But by the help of God, in order that We may crown this joy, We desire to fulfil, as far as lays in Our power, Our apostolic duty of charity by extending the plenitude of Our infinite spiritual treasures to those beloved children of the Church who, having died the death of the just, have quitted this world of strife with the sign of faith, and are branches of the mystical vine, though they cannot enter into everlasting rest until they have paid the uttermost farthing which they owe to the avenging justice of God.
6. We are moved to this both by the pious desires of Catholics to whom We know that Our resolution will be especially grateful, and by the fearful tortures which the souls of the departed suffer, but We are also animated by the custom of the Church, which, amidst the most joyous solemnities of the year, fails not to make a holy and salutary commemoration of the dead that they may be delivered from their sins.
7. Therefore, since it is certain by the doctrine of the Catholic Church, that the souls detained in purgatory are benefited by the prayers of the faithful, and especially by the august Sacrifice of the Altar, We think we can give them no more useful and desirable pledge of Our love than by everywhere increasing the offering of the pure oblation of the Most Holy Sacrifice of Our Divine Mediator, for the extinction of their pain. We therefore decree, with all the necessary dispensations and indulgences, the last Sunday of next September as a day of ample expiation on which will be celebrated by Ourselves, and equally by each of Our brethren the Patriarchs, Archbishops, and Bishops, and also by other prelates exercising jurisdiction in a diocese, each in his own church, whether patriarchal, metropolitan, or cathedral, a special Mass for the Dead with the greatest solemnity possible, and according to the rite ordered in the Missal for the Commemoration of all Souls.
8. We desire also that this should take place in the same manner in all parish and collegiate churches, both of the secular and regular clergy, and by all priests generally, provided that they do not omit the proper office of the Mass for the day where it is obligatory.
9. As to the faithful, We strenuously exhort them after Sacramental confession devoutly to partake of the Bread of Angels for the benefit of the souls in purgatory. We grant by Our Apostolic authority a plenary indulgence to be gained by such of the faithful, applicable to the dead, and the favour of a privileged altar to all those who, as has been said before, say Mass.
10. Thus those pious souls who expiate the remainder of their sins amidst such tortures will receive a special and opportune consolation, thanks to the life giving Victim which the Universal Church united to her visible head, and animated with a like spirit of charity, will offer to God that He may admit them to the dwelling of His consolation, to light and eternal peace."
