If Vespers was not immediately followed by Compline, the last of the daily Hours services, it was the custom to sing instead the seasonal Marian antiphon with its associated devotions. ‘Salve Regina’ was the antiphon sung at St Mark’s from the Octave of Pentecost to the first day of Lent – i.e. for most of the Church year – which may explain why Monteverdi supplied no fewer than three settings in the Selva morale
. This languorous and sensual setting for two equal voices shows clearly why Monteverdi was particularly fond of the medium of the duet, for it allowed him to explore the rhetorical devices of declamatory solo song while also allowing him to intensify them by giving them now to one voice, now to the other, now to both together, and through such repetitions to build larger-scale structures than would be possible with a single voice.
from notes by John Whenham © 2004