Orientales Omnes Ecclesias §36

³⁶ However, ostensibly for the protection of the complete integrity of their rite but in reality so that the unlearned people might more easily fall off from the Catholic faith, some crafty promoters of schism endeavored to reintroduce old customs, already in part obsolete. The Roman pontiffs, therefore, as in duty bound, openly denounced their clever and hidden machinations and decreed that "without consulting the Apostolic See no innovation was to be made in the rites of the liturgy, even on the grounds of restoring ceremonies thought to be more in conformity with liturgies approved by the same See, but only for very grave reason and by the authority of the Apostolic See."