Under Scott Metcalfe, Blue Heron’s “Christmas in Medieval England” at First Church Cambridge Friday dramatized Renaissance vocal music for the 21^st century,  leading to wonderful chance and challenging encounters with 15^th-century English carols, Sarum plainchant, and motets by Leonel Power and John Dunstaple.

There is no question that “Christmas in Medieval England” informed even from the start. There was a feeling of newness in perhaps the only truly familiar music on the program, Veni, veni Emanuel. Gathered around the altar lit with candles; men, with their backs to us, chanted the unison melody with intervening silent spaces. In this old but well-known 13^th-century hymn, these rests were completely new and fascinating to me as we sat in the darkened church.

From Metcalfe’s educative program notes, “This evening’s concert offers a small selection of music for the Christmas season that might have been heard in England in the 1440s, when the most modern of the works on the program were composed.” Still modern to my ears, if modern can mean fresh and contemporary, was the human voice deployed as it was last night. Michael Barrett, Pamela Dellal, Paul Guttry, David McFerrin, Owen McIntosh, Jason McStoots, Martin Near, Gerrod Pagenkopf, Mark Sprinkle, and Daniela Tošić, names familiar to many early music enthusiasts, created a vastness of space of absolute and utter beauty gyrating between the earthly and heavenly. It was that kind of coupling expression, emblematic of the Renaissance, which many perceive in the Mona Lisa.

Just before intermission, lights again went out in the nave. A Sarum plainchant issued forth at the candlelit altar. Veni redemptor genicium itself became darkened with a low drone under the minor-sounding mode (of Dorian?). With another piece, came the movement of singers on and off First Church’s unusually large performing area. Non-participating musicians could be seen seated on the perimeter, listening. Was it to be Christmas storytelling, a concert, a ritual? Blue Heron’s presentation was puzzling. Applause seemed strange; then again, it did not.

The uptempo, short phrases, and repetitions in the 15^th-century polyphony of Nowel’s Owt of your slepe aryse helped me focus, even if I could not fully understand the text. Ecce, quod natura (Behold, Nature) with Dellal, McIntosh, and Barrett, may very well have been the very favorite of all. This trio imparted Ecce’s simplicity with pureness, spotlessness, an enchanting exquisiteness.

However, the more complex textures of Sanctus / Missa Veterem hominem and Ave rex angelorum tested my concentration. With these, as with other like selections, I found myself unable to maintain focus. Modernity may have had played its role. Attention given to the moment, a sonority, an imitation—and these were breathtakingly tuned, splendid entities—rather than to the whole, the big picture, eventually became fatiguing. As to those numerous double leading tone cadences, the language of the day, all too often they would figure into the same, predictable dynamics, a pulling back, that also led to fatigue.

Metcalfe accompanied several of the pieces playing a harp built by Lynne Lewandowski of Bellows Falls, Vermont. According to Blue Heron’s Music Director, “The medieval harp twangs and crackles as it gut strings vibrate against the thin edge of the L-shaped bray pin; the sound is louder and more sustained especially in the bass, than that produced by a harp without brays.”

There was much to admire about the human voice as it was employed in earlier times and as it was re-envisioned through the extraordinary vocalizations of these young musicians.

David Patterson, Professor of Music and former chairman of the Performing Arts Department at UMass Boston, was recipient of a Fulbright Scholar Award and the Chancellor’s Distinction in Teaching Award. He studied with Nadia Boulanger and Olivier Messiaen in Paris and holds a PhD from Harvard University. www.notescape.net