Much of John Tavener's "Ikon of Light" is devoted to long, solemn reflections on Greek words like "Phos," which means "Light," and "Doxa" ("Glory"). These talismanic words are set, in the tradition of ancient liturgical chants, to music of timeless power, music hammered in bronze, carved in granite, music without a single superfluous note.

The work's American premiere last night in the Washington Cathedral was a significant event and the American Vocal Ensemble, conducted by Douglas Major, gave a performance worthy of the occasion. "I hope that this work will be performed with restraint and majesty," Tavener writes in an introduction to the published score. "It should unfold as a ritual in musical terms, attempting to express the inexpressible." That was precisely the effect last night.

The work is constructed in a large, almost symmetrical arch. At its center is a long "Mystic Prayer of the Holy Spirit," flanked on either side by the "Trisagion" ("Holy God, Holy and Strong, Holy Immortal, have mercy on us"), which in turn is flanked by the invocations of "Phos" and "Doxa" at the beginning, "Phos" and "Epiphania" at the end. The music uses a choir of up to eight parts and a string trio, some distance away, which represents "the soul yearning for God."

It would have been easy for a composer to bungle a project like this, but Tavener triumphs; he has produced a mystical meditation, a drama of emotions evoked and satisfied, and a rock-solid musical structure. He has also arranged the dynamics of the music, its surges and pauses, to take full advantage of the resonant acoustics found in a building like the cathedral.

The program also included the "Messa sopra 'L'Aria della Monica' " by Girolamo Frescobaldi, a well-structured work of harmonic and polyphonic textures, but not comparable to the Tavener.