Baroque delivers a rare Vivaldi in vivid color

It is a lovely and somewhat peculiar work, written in 1716 for the girls of the orphanage where Vivaldi worked, and labeled "A Sacred Military Oratorio." It adapts a story from the apocrypha featuring Juditha, a Jewish widow who, in order to save her embattled city, seduces and later beheads Holofernes , a general of Nebuchadnezzar's army. The libretto by Giacomo Cassetti gets pretty gory -- in one recitative, Judith urges her servant Abra to put the general's severed head in a bag as they make their escape -- and Vivaldi's vocal writing sometimes seems more concerned with florid display than with deeply probing the complexities of his characters' plights. But the music is consistently imaginative -- and occasionally breathtaking -- in its use of orchestral color.

For many of the individual arias, Vivaldi carves out wonderfully distinctive worlds unto themselves, often by pulling out solo instruments from the orchestra. Most extraordinary on Saturday night, the second of two performances, was the moving aria "Veni, veni, me sequere fida" in which Juditha compares her lament to that of a turtle dove, and from the orchestra arises the remarkable voice of the chalumeau, a clarinet-like instrument with a more reedy but beautiful and yes, dove-like, timbre as expertly rendered by Nina Stern . In other arias, Vivaldi likewise enfolds the cries from his characters' tender hearts in similarly delicate obbligato writing for oboe and organ, for viola d'amore, and even for mandolin.