One of my favourite motets by Tomás Luis de Victoria is the four-voice O quam gloriosum, a motet indicated for the feast of All Saints. It was one of his most published works with the first print in the 1572 book of motets with reprints in 1583, 1585, 1589 and 1603 a sign that it was a popular work in the sixteenth century.
This motet was also used later as a model for a four-voice parody mass. As the case of O magnum mysterium, it is interesting to notice that the parody masses were based in well-known works, and the O quam gloriosum seems to be the case. I believe this not only established the mass as a well-known and popular work but also enhanced the already notoriety of the model in which it was based on. This is the case of several of Palestrina’s masses which are based on his own motets enhancing not only the mass but also its model. I suppose that the young Victoria might have learned something from the well-established Roman master.
One of the features that have certainly contributed to the popularity of the O quam gloriosum was the liveliness of the motet, contrasting to other more “serious” of Victoria’s works. The opening phrase on the letter “O” strikes the ear with the rising degrees in a homophonic texture invoking the praise of the saints. The rhythmic texture gets thinner at “sequentur Agnum”, when a syncopated motive used in a point of imitation where all voices participate (in a canonic movement) leads to a series of suspensions causing some tension. An “Alleluia” closes the work, with a jubilant character such as in the O magnum mysterium, in a very long imitative section with fast descending lines.