To download the song, either right-click (Mac: ctrl+click) the player above and select ‘save audio as’, or right-click (Mac: ctrl+click) this link and select ‘save link as‘.
It’s taken me this long to realise that this carol, and ‘Hark the Herald Angels Sing’ both begin with an anacrusis in the notation. The reason must be a dancey one, I think, because it doesn’t do the words any favours in either case. The original German of Mendelssohn’s chorus that gave us the tune for Hark the Herald Angels Sing begins ‘Vaterland in deinen Gauen’, and if you’re going to sing Vaterland, surely you want a big Vat- on 1, you don’t want to dissipate it in some dainty gavotte-like anacrusis. But respecting the anacrusis rather than trying to force it back on to ‘one’ gives the music rather a nice lilt, I think, and suggests a different kind of movement.
Update, Nov. 2018: In the years since writing this post, I’ve understood that this probably has everything to do with what William Nathan Rothstein refers to as “national metrical types” and I’m wrong to talk about ‘Gavotte type anacruses.” It’s a long story. 7,500 words long, as it happens, which is the length of the article I’m preparing on this for an Oxford Handbook.
Henry Gauntlett, who wrote the tune, is a much bigger name in the history of organs and hymns than you might suppose from this example. He apparently had a Lambeth Doctorate, a phrase I hadn’t heard before. It sounds like a euphemism for something involving drugs and violence, but it isn’t. Read more here.