About this blogger:
A theorist, organist, and conductor, Jeff Ostrowski holds his B.M. in Music Theory from the University of Kansas (2004), and did graduate work in Musicology. He serves as choirmaster for the new FSSP parish in Los Angeles, where he resides with his wife and children.
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“The Church has always kept, and wishes still to maintain everywhere, the language of her Liturgy; and, before the sad and violent changes of the 16th century, this eloquent and effective symbol of unity of faith and communion of the faithful was, as you know, cherished in England not less than elsewhere. But this has never been regarded by the Holy See as incompatible with the use of popular hymns in the language of each country.”
— Pope Leo XIII (1898)

Rehearsal Videos • “O Magnum Mysterium” (Victoria)
published 7 December 2015 by Jeff Ostrowski

953 O Magnum Mysterium Victoria IKE MANY of his fellow composers, TOMÁS LUIS DE VICTORIA (†1611) was a Roman Catholic priest. 1 His distinctive religious sensibility was apparent in his compositions, and a striking example is his setting of the Responsory for the Octave Day of Christmas:

    * *  O Magnum Mysterium (PDF)

I’ve created rehearsal videos for each voice to help amateur choirs. It can be a bit frightening to tackle such a masterpiece—and sometimes feels like “rushing in where angels fear to tread”—but hopefully these practice videos help:

EQUAL VOICES : YouTube   •   Mp3 Audio

SOPRANO : YouTube   •   Audio

ALTO : YouTube   •   Audio

TENOR : YouTube   •   Audio

BASS : YouTube   •   Audio

Renaissance composers frequently (but not always) left it up to the singers to add the sharps and flats. The rules for “musica ficta” are fairly straightforward, but—as many Renaissance theorists pointed out—problems arise when the various rules conflict.

Many editions of Victoria’s O Magnum Mysterium have a sharp for the Sopranos in measure 21 but a natural for Tenors in measure 20, even though they sing the exact same phrase. Here’s the Tenor line in a 1582 manuscript:

959 TENOR 1583b

There are reasons why Tenors might not sing a sharp—while the Sopranos do—but there are more compelling reasons why they ought to match. When I looked at a 1572 manuscript, I found that missing sharp for the Tenors:

958 O Magnum Mysterium Victoria 1572

Now I will reveal the “dirty little secret” about musica ficta: we prefer it how we learned it. In other words, we tend to prefer a piece the way we sang it the first time. For example, some editions have the Sopranos in measure 42 singing a natural—not a sharp—and there are compelling reasons for this; but in my edition, I keep the “traditional” way.

For those of you who know this piece, have you ever sung directly from the part book? Here’s how the TENOR would have been sung in the 16th century.


1   Cristóbal de Morales (†1553), Costanzo Porta (†1601), Lodovico Viadana (†1627), and Gregorio Allegri (†1652) were all clerics, and many more composers could be mentioned.