«UT QUEANT LAXIS RESONARE FIBRIS».
- Hymn of Vespers in the Office of the feast of s. Giovanni Battista, written by Paolo Diacono, a Benedictine monk of the 8th century.
Inspired by the Gospel of s. Luca, the poet highlights the portentous signs that preceded the birth of the Forerunner. The first stanza has great historical-musical interest because the initials of each hemistich, which follow one another in the six sounds of the hexachord, were used by Guido d'Arezzo to give the musical notes their names in the new system of solmization.
BIBL.: G. G. Belli, Gli inni dei Breviario tradotti, Roma 1856, pp. 266-69; L. Venturi, Gli inni della Chiesa tradotti, Firenze 1880, p. 323; C. M. Dreves - C. Blume, Anal. hymn., vol. L, Lipsia 1908, pp. 120-23; C. Albin, La poésie du Breviaire, Lione s. a., pp. 280-85; A. Mirra, Gli inni del Brev. romano, Napoli 1947, pp. 214-16.