Some years later Palestrina based a Mass setting on the motet Confitebor tibi Domine
, a common practice at the time. The Missa Confitebor tibi Domine
was copied into one of the papal choir’s manuscript choirbooks in about 1577 (when Palestrina was its official composer) and was subsequently published in 1585. The Mass is composed for two separate choirs—called ‘cori spezzati’ in Italian—with a clear division into two equal groups and with both bass parts avoiding the fifth of the harmony, necessary if the choirs are to be physically separated. In the Sistine Chapel, however, such division was not possible since the singers occupied a single ‘cantoria’ on the right-hand wall, but plans for publication would have led Palestrina to write it in the increasingly popular polychoral style for choirs placed on separate platforms or galleries. Like other so-called parody or imitation Masses, the six movements re-mix musical material from the motet, adapting it to the new words and adding new material where necessary. The opening of the motet is used for the beginning of all the major sections of the Mass, and for most of its sub-sections, while its end is used for the final bars of the Gloria, Credo and Agnus Dei. The scales used to highlight the word ‘Exsulta’ in the motet are put to good use in the final Kyrie and at a number of points in the Credo and Sanctus. Both of these movements have extended sections for four voices.
from notes by Noel O'Regan © 2018