This 37-year-old British composer (who writes film scores and leads a rock band) harkens back to the medieval era of pilgrimages to the Cathedral of Santiago de Compostela in Spain, site of some rather complex miracles attributed to St. James. Though utilizing 11th-century texts in the Codex Calixtinus and tools of medieval composition like bass drones, hypnotic chant and scales with only passing references to major and minor keys, Path of Miracles is anything but obscure. It's about ordinary people "beating on the doors of heaven" (as one portion says) and receiving no reply. It feels perfectly immediate.

At the outset, singers deliver a primal series of long glissandos/crescendos. Texts recount myths about evil masquerading as the holiest of figures. Some musical ideas exist simultaneously but separated by dissonant intervals, suggesting a photograph that's double-exposed. There are echoes of the infectiously earthy melodies and punchy rhythms of the 13th-century song collection Cantigas de Santa Maria. That's quite a range of expression for unaccompanied chorus, which must seem like a complete musical entity whatever its practical limitations. And choruses, of course, aren't orchestras. Or are they? Path of Miracles aspires to the psychological magnitude of Mahler and often gets there.

The 22-voice Crossing choir wasn't consistently on top of technical matters, though music director Donald Nally seemed not to want typical surface polish in an appropriately raw, declamatory reading, emphasizing the music's originality and letting its Anglican roots remain in the foundation - until the undeniably Anglican final movement. Objectively speaking, I hoped the composer would surpass himself rather than falling back on familiarity. But in the thick of Nally's absorbing performance, with everything emotionally growing out of what came before, objectivity was only possible in retrospect.

Though the piece needs no atmosphere in order to communicate, the Presbyterian Church of Chestnut Hill was darkened down to a seance-level wattage with the words projected onto the rear wall, often looking as if carved in weathered stone. That extra-mile touch, coupled with great artistic dedication, makes the Crossing a Philadelphia institution others should look to for standards and inspiration.