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