Joel Cohen and the Boston Camerata recorded this Christmas LP in 1975. A great mixture of ancient texts and melodies.
From the album notes:
The midwinter date of the festival of Christ’s nativity coincides with many pagan celebrations of the winter solstice, and most particularly with the Roman Dies sol invictus (“the day of the unconquered sun”), December 25. Certain pre-Christmas forms and practices survived and intermingled with the Christian holiday, and elements of the Roman Saturnalia, a year-end bacchanal, are still present in our holiday merrymaking at Christmastime. But the specific themes of Annunciation, Advent, and Nativity make Christmas a celebration unique among mankind’s other midwinter rites. By the 6th century, most elements of the medieval celebration of Christmas were in place.
Read more of the notes here: http://www.bostoncamerata.com/amedievalxmas.html