Carol of the Bells
The four-note figure that never stops started life as Shchedryk, a Ukrainian song for the new year rather than for Christmas. Composer Mykola Leontovych arranged it for choir in the 1910s, and it was performed in Kyiv in 1916. The original words have nothing to do with bells: a swallow flies into a house and promises the family a prosperous year.
The Ukrainian National Chorus brought the piece to America on tour in the early 1920s, including a concert at Carnegie Hall in 1922. In 1936 Peter Wilhousky wrote new English words, and the swallow became the bells that most listeners know today.
O Holy Night
The French original, Minuit, chrétiens, was written in 1847: words by Placide Cappeau, a wine merchant and poet, music by Adolphe Adam, the composer of the ballet Giselle. The English version familiar today came from John Sullivan Dwight in 1855.
You will often read that it was the first piece of music ever broadcast on radio, on Christmas Eve 1906. That story comes from the inventor Reginald Fessenden's own later accounts, and historians have questioned whether the broadcast happened as described.
Hark! The Herald Angels Sing
Charles Wesley wrote the words in 1739, beginning "Hark how all the welkin rings" - welkin being an old word for the sky. The opening was later changed to the line everyone sings now.
The tune came more than a century later, and from an unlikely source. Felix Mendelssohn wrote it in 1840 for a festival celebrating Gutenberg and the printing press. Mendelssohn reportedly felt the music would not suit sacred words. In 1855 the English organist William Cummings fitted it to Wesley's text anyway, and the pairing stuck.
O Come All Ye Faithful
Originally the Latin hymn Adeste Fideles, it is usually attributed to John Francis Wade, an English Catholic who copied and sold music manuscripts in France in the 1740s. The English translation most people sing was made by Frederick Oakeley in the 1840s.
O Little Town of Bethlehem
Phillips Brooks, a minister in Philadelphia, visited Bethlehem in 1865 and wrote the words a few years later for the children of his Sunday school. His church organist, Lewis Redner, wrote the tune. In Britain the same words are usually sung to a different melody, Forest Green, an English folk tune arranged by Ralph Vaughan Williams.
Jingle Bells
The most famous Christmas song in the world does not mention Christmas. James Lord Pierpont published it in 1857 as One Horse Open Sleigh, a song about winter sleigh rides and, in the later verses, a crash in the snow. Two towns, Medford in Massachusetts and Savannah in Georgia, both claim it was written there, and the question is still argued.
It does hold one undisputed record. In December 1965 the Gemini 6 astronauts played it on a small harmonica and a set of bells they had smuggled aboard, making it one of the first songs performed in space.
We Wish You a Merry Christmas
A traditional song from the West Country of England, sung by carollers who went from house to house expecting something in return - hence the insistent demand for figgy pudding and the refusal to leave until it arrives. Its popularity in the twentieth century owes much to an arrangement by Arthur Warrell, published in 1935.
Why the old tunes last
Most of these carols have outlived several changes of words, language and even purpose. What survives is the melody. That is one reason instrumental versions work so well as background music: without the words, they are simply familiar tunes that make a room feel like December.