Nuper rosarum flores (Recently Flowers of Roses) is a motet composed for the consecration of the Florence cathedral on March 25, 1436. The title of the piece is rooted in the name of the cathedral, Santa Maria del Fiore, or St. Mary of the Flower.
Nuper rosarum flores is an isorhythmic motet with a remarkable rhythmic structure. The talea of this piece comes in four different forms, all differentiated by the meter. Therefore, Nuper is a mensuration canon. The four talea's of the two tenor parts are written in meters with a proportion of 6:4:2:3, which is believed to represent the structure of the cathedral for which it was written.
The color of the two tenor parts are directly correspond with the talea in a one to one relationship. The color is taken from the plainchant Terribilis est locus iste, and they are identical, except that they are a perfect fifth apart. While the third and fourth parts do not adhere to isorhythmic parameters, they each reuse thematic material during each repetition of the talea and color.
The text is divided in a more complicated manner, including stanzas of text being broken up by the repeat of talea and color. For example, the first talea and color uses the first stanza and most of the second, but the third talea and color only uses three lines of the fourth stanza. Although odd, the textual structure is directly correspondent with the meter of each strophe (6:4:2:3).
Nuper is a bit of an oddity when it comes to Dufay's music. The isorhythmic motet is a bit outdated for Rennaissance, but it shows Dufay's concern for mathematical relationships. This can also be seen in many of his compositions, including the ballade, Resvellies vous et faites chiere lye, in which the length of the piece in breves is in direct correlation with the number of notes in many phrases. For more information, see Josh Golden's analysis on Dufay: Resvellies vous et faites chiere lye.
Nuper rosarum flores is particularly interesting for its seemingly codified representation of mathematical proportions of the St. Florence Cathedral. Also, it is in itself a representation of the erection of the St. Florence Cathedral and what that meant regarding the shift from Ars Nova to Early Rennaissance. As an isorhythmic motet, one immediately thinks pre-Rennaissance, but there are many elements of Nuper that make it blur the line and mark a shift of styles.
Vallemy, Andreas. "Dufay's Synthesis of Ars Nova and Renaissance Techniques in Nuper Rosarum Flores," November 23, 1997, http://www.haverford.edu/musc/multimedia/music230/voellmy/dufay2.html . Weiss, Piero and Taruskin, Richard. Music in the Wester World. New York: Schirmer Books, 1984. p. 81-82.
Wright, Craig. "Dufay's Nuper rosarum flores, King Solomon's Temple, and the Veneration of the Virgin." Journal of the American Musicological Society 47, no. 3 (Fall 1994): 395-441.