"L'Enfance du Christ" by Hector Berlioz, well performed over the weekend by the Montgomery Chamber Orchestra and the Masterworks Chorus, is not exactly a piece of Christmas music, but it's inseparable from this time of year. It narrates not the birth of Jesus Christ, the angel's message to the shepherds, the arrival of the Magi and all the other familiar details of the story, but the immediate aftermath.

"At that time," the tenor narrator begins the story, "Jesus had just been born in the manger, but no miracle had yet made him known." From there the story goes on to Herod's destructive paranoia, the holy family's flight into Egypt, their problems in finding a place to stay and their eventual acceptance by a family of Ishmaelites. The words and music, both by Berlioz, have a tenderness and delicacy unique not only in his works but in all music.

The composer who graphically used four antiphonally placed brass bands to portray the end of the world in his "Requiem," who produced spectacles of epic scope in "Les Troyens" and "Benvenuto Cellini" and who escalated the art of orchestration into a new dimension for the Halloween-style phantasmagoria of his "Symphonie fantastique" was also capable of the most delicate touches and subtlest nuances when the occasion demanded. "L'Enfance du Christ" shows the intimate, miniaturistic side of Berlioz's genius, and it is a treasure even for those to whom the text has no particular relevance.

The music announces its specialness right at the beginning in the pulse, the tension and dark, subdued color of the "Nocturnal March" in Scene 1. The flavor is more like the familiar Berlioz in the brilliance and vigor of Herod's dream and aria of wrath, but it comes back in hundreds of small details: the woodwind introduction to Mary and Joseph's first duet, the delicate touch of timpani portraying Joseph's timid knocks on a stranger's door, the atmospheric use of an offstage women's chorus singing a cappella to evoke angel voices, the wonderfully descriptive orchestral music that portrays the family's painful trip across the desert, the lovely trio for two flutes and harp that welcomes them to their new home.

Above all, the special character of the work is embodied in the archaic and timeless style of the "Shepherds' Farewell to the Holy Family," an unpretentious little chorus that Berlioz dashed off impromptu, not knowing that it would grow, over the years, into this curious, lovely composition midway between opera and oratorio. In purely musical terms, without considering its subject, "L'Enfance du Christ" is constantly refreshing, frequently dazzling.

Piotr Gajewski, the Montgomery Chamber Orchestra's music director, was alert to every nuance of the music and superbly in control of his performers. The Masterworks Chorus responded to the work's varied demands with a high level of proficiency, and several of its members sang effectively in the smaller solo roles. Outstanding among the soloists was bass Peter Loehle as both Herod and the Ishmaelite who welcomes the holy family at the end. Tenor Matthew Chellis began well and improved steadily throughout his performance as the narrator, and mezzo-soprano Karen Lykes was effective in the role of Mary.