CAMBRIDGE - Few forms of art seem more rarefied than Renaissance polyphony. Its flow of religious praise melded to sinuous contrapuntal melodies appears to belong not just to another time but to another universe. Yet at Sunday's concert by the extraordinary Blue Heron Renaissance Choir, the real world managed to creep subtly and uneasily in.
The largest single work on the chorus's all-English program was the "Missa Mater Christi" by John Taverner. This Mass setting is based on a motet of the same name, and each of its four polyphonic movements - the opening Kyrie is chanted - reuses and explores music from the motet, teasing out its material into a sweeping series of variations.
Interestingly, music director Scott Metcalfe dispersed the Mass's movements over the program's two halves, interweaving them with motets by William Byrd and John Mason. Byrd's compact and vigorous "Vigilate" was the curtain raiser for the Gloria and Credo. Their soaring upper lines and glittering harmonies seemed to bespeak the simple joy of God's presence and the solidity of faith.
Doubt began to creep in during Mason's complex "Quales sumus O miseri." Its title translates as "What are we, O wretches," and it sets an unusually graphic and melancholy text for five low voices. Though it is a plea for the Virgin's mercy, much of the music remains transfixed in darkness.
The mood was extended in the second half, as three Byrd motets surrounded the glowing Sanctus and wistful Agnus Dei of Taverner's Mass. Each motet invoked the image of Jerusalem within themes of distance and inaccessibility. "Quomodo cantabimus" pictured it as the longed-for site of return from exile. "Ne irascaris," one of Byrd's greatest creations, saw the holy city in ruins, lamenting "Jerusalem is forsaken." And "Haec dicit Dominus," with its shifting tonalities, held out the bare possibility that Israel's children "shall return to their borders."
Though Metcalfe's program note made a brief allusion to religious conflict, there was no didactic point made here, no simple sloganeering. But the program was a reminder that even in the ethereal company of music more than 400 years old, the discord of the present is always present. It was a striking, if unsettling, realization.
In its eight seasons, Blue Heron has established itself as the city's finest purveyor of Renaissance polyphony, and Sunday's concert only enhanced that impression. Its 14 voices create a sound that's almost sensually rich, yet balanced and incandescent. Metcalfe maintained superb control over texture and dynamics. A well-filled First Church indicated that the chorus already has a devoted following, one that should grow during its ninth season.