Blue Heron basks in medieval light

CAMBRIDGE - From out of the darkness of the First Church in Cambridge, Congregational, Saturday night soared the words “Veni, veni, O Oriens!’’ - “Come, come, O Morning Star!’’ It was a reminder that, for medieval England, the star of Bethlehem was a symbol of the light that dispels the gloom of bleak winter. Blue Heron’s stellar “Christmas in Medieval England’’ program followed that trajectory, the choir collecting about the candle-shadowed altar to sing “Veni, veni, Emmanuel!’’ before coming forward into the chancel and the light.

There was a particular glow to this local choir’s sound. For years, the austere, ethereal purity of the Tallis Scholars has been the standard for medieval and Renaissance vocal polyphony. Blue Heron offers a full-bodied, even lusty alternative, with greater pointing of the text. The very first word of the evening, “veni,’’ was given a clipped emphasis that had me listening to this familiar hymn in a way I never had before. In her solo traversal of the 13th-century Annunciation hymn “Angelus ad virginem,’’ Daniela Tosic let her voice spread and deepen on “salutem,’’ a word indicating the salvation of humankind.

The program ranged from the 13th to the 15th century, encompassing Annunciation hymns and Christmas carols and sections from the Mass, with Blue Heron music director Scott Metcalfe accompanying some pieces on the harp and joining the choir as a 12th member on others. Both texts and music were full of twists: Mary was identified as the “empresse of helle’’ and Jesus as our “blessyd brother,’’ and Leonel Power’s Gloria was as full of thorns as roses. “Nowel syng we bothe al and som’’ got such a hearty rendition, you might have thought it was celebrating the dinner arrival of the boar’s head and not the coming of the King of Peace. One selection alone, John Dunstaple’s “Gaude virgo salutata/ Gaude virgo singularis,’’ suffered from oddly weak enunciation. At the end of the Sanctus from the 15th-century Missa Veterem hominem, on the other hand, the choir burst forth like the heavenly host over the shepherds.

The encore was the 15th-century carol “Nova, nova,’’ which proclaims the news of Jesus’s birth. As they did at the beginning with “veni,’’ the performers underlined each “nova,’’ as if they knew they had something special to sing about. Nova was also the word that described a new star in the sky. Kind of like Blue Heron itself.