John Joubert's Pro Pace Motets for unaccompanied double choir (SSAATTBB).

These three motets, Pro Pace, though written at different times, form a triptych on the subject of peace. The first to be composed was Libera Plebem, composed for and first performed at the Attingham Park Summer School, 1955. The text is a 9th century Latin poem, in the form of a prayer for deliverance from the Black Death.
The second motet, which was composed last, is a 10th century Latin lament for the day on which man first invented weapons for use against his own kind, and a protest against such use.

The final motet, the longest and most elaborate of the set, traces the Passion story from its sombre and tragic beginnings to its hopeful and triumphant end. It is a setting of a Latin poem by Peter Abelard, and its function in the triptych is to equate the victory of Christ's Passion with the eventual victory of non-violence.