In Monteverdi's time, early 17th century, forward-looking composers wanted to enlist music in the wars of truth. This was the beginning of our modern age, and Monteverdi counts among our prophets. In key with his time he shared the impulse to soul-saving and said in prefaces what he thought he was up to. Words and deeds aren't the same, though, and the music he made has no purpose but itself. Also it looks backward and forward. Master of the Second Practice, a new style in his young manhood, he highlighted words, projecting their truth through his music. In the old-fashioned style, the music, imperious, rode over the words. Monteverdi, backward-looking, mastered the First Practice, too. One side of him knew it for the more capacious vessel. The secret of his genius, this contrariness makes him hard to pin down.

Primarily a secular composer, he left nine books of madrigals and 15 dramatic entertainments. Seven survive, among them the first successful opera. He wrote sacred music as well, hoping to get on in a world where music and religion were still closely intertwined. Psalms, masses, responsories, motets, hymns, and so forth, the sacred pieces make an alphabet of forms. Some sound like Gregorian Chant, the Missa da Capella, for instance, and parts of the Christmas Vespers. But in the Vespers the swelling brass sounds like the Gabrielis, predecessors of Monteverdi in Venice. Then the music changes, becoming "baroque." The 23 motets, Sacrae Cantiunculae, "little sacred songs," conform to strict polyphony, not different to my ear from the music of Palestrina. But some of these motets, trembling almost erotically, return on