MAINTAINING THE COMPLETELY UNCHANGED LATIN ROMAN CATHOLIC MASS DECREE QUO PRIMUM, ST. PIUS V, JULY 19, 1570
"By this our decree, to be valid IN PERPETUITY, we determine and order that NEVER shall anything be added to, omitted from, or changed in this Missal. . .At no time in the future can a priest, whether secular or order priest, ever be forced to use any other way of saying Mass. And so as to preclude once and for all any scruples of conscience and fear of ecclesiastical penalties and censures, we herewith declare that it is in virtue of our Apostolic Authority that we decree and determine that this our present order and decree is to last in PERPETUITY and can never be legally revoked or amended at a future date. . . And if anyone would nevertheless ever dare to attempt any action contrary to this order of ours, given for all times, let him know that he has incurred the wrath of Almighty God and of the Blessed Apostles Peter and Paul."