We expect to hear it every New Year’s Eve, again at the stroke of midnight, and off and on through New Years Day. It starts even earlier, when we watch It’s a Wonderful Life. We may not know the lyrics to “Auld Lang Syne,” but we sing it anyway. Where did that song come from in the first place?
The song originated as a poem, but it probably wasn’t written by Robert Burns as is commonly believed—at least not entirely. The poet was simply the first person to write down an old Scottish folk song (it bears more than a passing resemblance to “Old Long Syne,” a ballad that was printed by James Watson in 1711). Burns himself said, “I took it down from an old man,” and whether it was transcribed or co-authored, it’s safe to say that the “Auld Lang Syne” we know today is some combination of an old poem and Burns’ creative input.
In any case, Burns sent a copy of the poem to a friend in 1788 and wrote: "There is more of the fire of native genius in it than in half a dozen of modern English Bacchanalians!" Later he contributed it to the Scots Musical Museum.
The words really have nothing to do with the new year, or any holiday. That’s a more recent tradition. Read about the history of the song, its meaning, and how we use it, at mental_floss.