Canons and pearls

Victoria Missa Simile est regnum cælorum
Guerrero Ave Virgo sanctissima

The Gospel reading for the 17th Sunday in Ordinary Time (Year A) is taken from Matthew (13: 44-52) ‘The kingdom of heaven is like…’ (Simile est regnum cælorum), a text repeated in the Communion Antiphon. Victoria’s Mass is a parody of Guerrero’s motet of the same title; however, the text of Guerrero’s motet is a different simile from later in Matthew’s Gospel (20: 1-4), so, while Victoria’s Mass ties in liturgically in title, if not in origin, Guerrero’s motet doesn’t. Instead, we are singing his wonderful motet Ave Virgo sanctissima which, far from being a random choice, fits in in two ways.

The first is its text: the Gospel talks about the kingdom of heaven being ‘like a merchant seeking fine pearls’ (Simile est regnum cælorum homini negotiatori, quærenti bonas margaritas). The anonymously-authored text of the Guerrero describes the Blessed Virgin Mary, among many other beautiful images, as a ‘precious pearl’ (margarita pretiosa).

Secondly, both pieces contain canons — a musical device whereby one voice, perhaps unwritten, obtains its music from that of another. This can be done by simple repetition or by more headache-inducing inversion or transposition. Victoria and Guerrero use the former, a Canon ad unisonum (at the same pitch). 

In the Guerrero, both soprano voices sing the same music, one following the other, both fitting with the three lower parts which sing throughout. In the second Agnus Dei, Victoria expands the single choir of four voices used throughout the Mass to two choirs of four voices, the second choir repeating the music of the first. Structurally, the canon in the Mass is more perceptible as one choir answers the other, but the casual listener is more likely to hear the Guerrero without recognising the academic showmanship on display. Both are wonderful examples of masterful canonic writing. Composing a canon isn’t especially difficult, but writing one that, for all its possible complexity, enables the music to unfold naturally without any clunkiness — the audible sign of the academic at work — is much harder. 

Both these works are perfect pearls of liturgical music, and, appropriately, the programming of one followed the programming of the other.