(Lyrics by H.W. Longfellow, 1863; using John Baptiste Calkin's melody, 1872)

Longfellow's reflection on Christmas, violence and personal loss during the American Civil War.

Some context, lifted from wikipedia:
In 1861, two years before writing this poem, Longfellow's personal peace was shaken when his second wife of 18 years, to whom he was very devoted, was fatally burned in an accidental fire. Then in 1863, during the American Civil War, Longfellow's oldest son, Charles Appleton Longfellow, joined the Union Army without his father's blessing. Longfellow was informed by a letter dated March 14, 1863, after Charles had left. "I have tried hard to resist the temptation of going without your leave but I cannot any longer", he wrote. "I feel it to be my first duty to do what I can for my country and I would willingly lay down my life for it if it would be of any good." Charles was soon appointed as a lieutenant but, in November, he was severely wounded in the Battle of Mine Run. Charles eventually recovered, but his time as a soldier was finished.

Longfellow wrote the poem on Christmas Day in 1863. "Christmas Bells" was first published in February 1865, in Our Young Folks, a juvenile magazine published by Ticknor and Fields. References to the Civil War are prevalent in some of the verses that are not commonly sung. The refrain "peace on Earth, goodwill to men" is a reference to the King James Version of Luke 2:14.