Choruses and audiences LOVE double-choir music, most famously the Bach motets Komm, Jesu, KommFurchte dich Nicht, and Singet dem Herrn. But most of us have only the most general idea where this kind of choral composition originated.

The standard one-line answer is that the balconies in the magnificent St. Mark's Cathedral in Venice allowed for two separated musical forces, and that choirmaster Giovanni Gabrieli fully developed the impressive effect of alternating or echoing choirs. This characterization captures double-choir's public-affairs iconic moment. Whereafter European composers flocked to this center of musical sophistication, and carried the double-choir technique along with other precursors of the Baroque back to their cathedrals and courts.

There is no known liturgical or dramatic need for a two-choir form. The virtuosity needed to compose these pieces and the forces and rehearsal time needed to perform them might suggest that they are simply compositional acrobatics, perhaps an excess of the late Renaissance. To look a little deeper, there are some important antecedents to this musical photo op in late 16th c. Venice.

Antiphonal music is prefigured by the archetypal alternation between a leader's call and a group's (perhaps a congregation's) response. Some scholars see this structure in the Psalms, suggesting that antiphony was part of ancient Hebrew worship. Ignatius of Antioch is said to have introduced antiphony into early Christian (c. 100 CE) worship after seeing a vision of two choirs of angels. An appealing prefigurement for our concert!

Medieval Christian antiphony retaining the call & response element developed from two distinct voices and roles into the polyphonic (many-voiced) technique we associate with Renaissance motets, in which the voices carry equal emphasis and none "has the melody."

The center of Renaissance polyphony was northern Europe, especially the Netherlands. By the beginning of the 16th c., Josquin de Prez and other Franco-Flemish composersemblemized the Ars Perfecta.  One of this school of accomplished composers, Adrian Willaert, was hired as St. Mark's choirmaster in 1527.  Josquin had traveled in Italy in his youth in the 1480s, and the exchange of influence was certainly a two-way street.

St. Mark's Basilica was built at the end of the 11th. c. as a giant space with many domes and two organs and choir lofts on opposite sides. Other Venetian composers before Willaert had followed the obvious suggestion to write music for two choirs, but this had not become a coherent style or movement. Willaert is recognized as a champion of this technique during his tenure, composing and performing much music for two separated alternating choirs and publishing "Salmi Spezzati" ('"separated psalms"), an antiphonal setting of psalms and the first published polychoral compendium. This publication became famous and spawned broad imitation. One of Willaert's pupils and imitators was Andrea Gabrieli, who taught his nephew Giovanni. Giovanni would become the most influential and imitated composer in Europe in his time, his name firmly linked to the Venetian Polychoral Style. Choirs imitated each other, echoed each other, and overlapped to glorious effect. Heinrich Schutz, Hans Leo Hassler, and other Germans who studied with him later seeded the development of the German Baroque.

Oddly enough, this suggestion of architecture-as-destiny probably isn't accurate. An earlier Franco-Flemish master, Martini, had written a set of psalms for antiphonal double choir in the 1470s.  Like others in his school, he had employment by the aristocracy of Italy, but he had no separated musical field to populate.  There were also others before Willaert. So why?

Perhaps inspiration came from the structure of the Psalms themselves.