Rhodes said she disagrees with those who claim “While Shepherds Watched Their Flocks at Night” is the first complete Christmas carol because it is a 16th-century tune written in the 19th century with 17th-century lyrics was combined.

“I still have a bone to pick,” she said, pointing out that “Adeste Fideles,” or “O Come, All Ye Faithful,” is the first.

“That existed in 1640,” she said. “I could bet that this was one of the first real Christmas songs in full form that we have, which is pretty nice.”

She said Puritan opposition to Christmas celebrations in the 17th century disrupted the development of carols in England until the early 18th century.

“We had a little break back then,” she said.

“When we talk about Christmas carols being banned and there being no more music in churches, people still did that. They would get together in secret and sing their Christmas carols, and so we have the remnants of some of those older pieces,” Rhodes said.

In the early 19th century, people began collecting, documenting, and publishing the Christmas carols they remembered. In 1822, Davies Gilbert published “Some Old Christmas Carols, with the Tunes to which They were Formerly Sung in the West of England.”

Queen Victoria, who reigned from 1837 to 1901, invited singing groups to perform at her palace at Christmas time.

“The Queen really enjoys singing Christmas carols and we have friends who are starting to collect all these missing Christmas carols,” Rhodes said.

The 1871 publication “Christmas Carols, New and Old” by John Stainer and Henry Bramley included “Good King Wensleslas,” “God Rest Ye Merry, Gentlemen,” and “The First Nowell.”

Rhodes led the group through a verse of “O Come, All Ye Faithful” and then sang a treble, a vocal line that embellished the melody to illustrate how Christmas carols evolve.

“No one had bothered with it for over a hundred years, and then we added the treble in 1960,” she said.