Musicae Sacrae §53

⁵³ It is not Our intention in what We have just said in praise and commendation of the Gregorian chant to exclude sacred polyphonic music from the rites of the Church. If this polyphonic music is endowed with the proper qualities, it can be of great help in increasing the magnificence of divine worship and of moving the faithful to religious dispositions. Everyone certainly knows that many polyphonic compositions, especially those that date from the 16th century, have an artistic purity and richness of melody which render them completely worthy of accompanying and beautifying the Church's sacred rites.