The California Bach Society went to church Friday night (St. John'sPresbyterian in Berkeley) with a performance that was not quite church andnot quite a concert. The program was a Christmas mass by Monteverdi, Missa in illo tempore, interspersed with a few works by other composers.

Monteverdi's choral writing in this mass is mostly in a conservative vein,limited in range and sonority, but with occasional flashes of color. Inthe Credo the choir responded to "Et incarnatus est" with a hush, and tothe repeated rising scales of the resurrection motif with enthusiasm. TheSanctus was beautifuly scored, starting in the higher voices and gatheringdepth as it went. The tenors brought out a falling scale pattern in theOsanna to great effect and led off the Agnus Dei with assurance. TheGradual was replaced by a women's trio, "Angelus ad pastores ait," nicelydone by Allison Zelles Lloyd, Andrea Fullington & Suzanne Elder Wallace.

Hugh Davies and Scott Whitaker manfully chanted long liturgical texts onone or two tones — the original minimalist music, in which an extra straytone is an event. They stayed in tune and phrased the words with care.For aficionados of chant or of Roman Catholic liturgy, it was a sterlingperformance. For others, the thought perhaps stole into the mind thatMonteverdi's music is best heard apart from its original authentic context.