Septuagesima ushers in sombreness in the Liturgy, as we prepare for Lent. As the week begins, let us remind ourselves of what we should be missing: the alleluia, and, soon enough, the angelic hymn. It is therefore a fitting time to look from the vantage point of gravity and soberness upon that Kyrie long ago named in honour of the angels.
The Missa de Angelis is a rather interesting grouping of ordinary chants. Contrary to the usual practice of naming ordinaries after the tropes of the Kyrie, Catholic scribes elected to name it after the Mass to which it was traditionally sung, the Votive Mass of Angels. By paleography and musicology standards, the collection is rather young: the Kyrie, from the 15th or 16th century; the Gloria, from the 16th century; the Sanctus from the 12th century; and the Agnus, from the 15th century. There are studies, however, that date it a century earlier.
For very obvious reasons, many hail it as the most performed Mass in the world. Many Traditional communities celebrate their Masses with Missa de Angelis as the ordinary. It probably eventually derived its status as the bread-and-butter setting for the Mass from the historical accident involving the 13th centenary of Saint Gregory the Great in 1904. To celebrate this milestone, Saint Pius X himself chose the Kyrie and the Gloria from the Missa de Angelis to be sung in the solemn High Mass at Saint Peter’s. (Sate your craving for more interesting tidbits about this Mass by reading pp. 375–378 here.)
But its gaiety, its exuberance, sometimes fails to impress the anal-retentive amongst us. Whether the opposition saunters along the line of “familiarity breeds contempt”, or endures provocation by a general distaste for unbridled joy, an unhealthy attachment to a single ordinary setting in the Liber usualis indeed spells the end of an instructive auditory and spiritual experience of the rest of the swag, so to say, in the Latin sacromusical treasury.
Having said this, we now go to our subject: the tropes. The tropes of this Kyrie are rather extraordinary in that they repetitively and metrically modify the melody. Unlike the tropes of Lux et origo or Cunctipotens genitor, Deus, whose words are plugged in directly into the individual notes of the melody, the tropes of De Angelis flourish somehow independently. They appear in the manner below (click on the image to open the file):
O King with everlasting heavenly power!