Perhaps I should clarify my post. Mediator Dei (1947) and Marialis Cultus (1974) have to be taken into full context of the situation in the times of which they were written. In the 27 years after Mediator Dei, people kept praying the Rosary as a pious substitute for the Holy Sacrifice of the Mass. The thinking goes from “I can’t understand what is going on, so I’ll just pray the Rosary instead” to “Well, Mass doesn’t do it for me spiritually, so it’s better if I just pray the Rosary.” The Mass is the highest form of prayer, not time to pray the Rosary. In Mediator Dei, Pius XII addresses the issue as a matter of faith and morals, in that although these pious devotions and the Eucharistic Sacrifice should not be confused with one another and the Holy Sacrifice of the Mass takes precedence, it is better for a person to pray the Rosary during Mass (to help enrich love for the Eucharistic Sacrifice) rather than to be a disinterested spectator ready to leave at a moment’s notice. In Marialis Cultus, Pope Paul VI addresses the issue as a matter of discipline. After Vatican II, Mass rubrics allow for the vernacular language, people can no longer use the “pious” excuse of, “I don’t understand Latin, so I’ll pray the Rosary instead.” Again, the Holy Sacrifice of the Mass is the highest form of prayer and takes precedence over the Rosary which Pope Paul VI reiterates in Marialis Cultus. Centering forms of prayer and meditations are good, but they should not be confused with or in competition with the Mass.