Even in 1974, the Sacred Congregation for Divine Worship was concerned about the trend of downplaying Gregorian Chant in favor of vernacular music. "Down the centuries, Gregorian chant has accompanied liturgical celebrations in the Roman rite, has nourished men's faith and has fostered their piety, while in the process achieving an artistic perfection which the Church rightly considers a patrimony of inestimable value and which the Council recognized as 'the chant especially suited to the Roman liturgy' [Constitution on the Liturgy, no. 116]... When vernacular singing is concerned, the liturgical reform offers 'a challenge to the creativity and the pastoral zeal of every local church' [Instruction, Musicam Sacram, no. 54]. Poets and musicians are therefore to be encouraged to put their talents at the service of such a cause, so that a popular chant may emerge which is truly artistic, is worthy of the praise of God, of the liturgical action of which it forms part and of the faith which it expresses. The liturgical reform has opened up new perspectives for sacred music and for chant. 'One hopes for a new flowering of the art of religious music in our time. Since the vernacular is admitted to worship in every country it ought not to be denied the beauty and the power of expression of religious music and appropriate chant' [Address of Pope Paul VI to Consociatio Internationalis Musicae Sacrae, 12 October 1973
]... At the same time, the liturgical reform does not and indeed cannot deny the past. Rather does it 'preserve and foster it with the greatest care' [Constitution on the Liturgy, no. 114]. It cultivates and transmits all that is in it of high religious, cultural and artistic worth and especially those elements which can express even externally the unity of believers." Can you believe the discussion in 1974 revolved around Gregorian versus vernacular chant? Today, in most places, I think the word "chant" is not even on the radar.
