How many tunes do you know for this carol? This one is the traditional Winchester Old:

http://www.hymnary.org/tune/winchester_old

You can find Lyngham here. It’s a “fuguing” tune, because of the way the voices split in the second part

http://www.hymnary.org/tune/lyngham_jarman

You can also fit this carol it to Ilkley Moor, good for a light-hearted change, or for keeping going when on a cold winter walk in the Christmas season.

The Voiceworks Christmas (OUP) Anthology has two “Gallery” style versions. Because the words follow a rhythm called “Common Metre”, they will fit many, many different tunes – aha, now we are entering a new field of exploration. Hymns are sorted by metre, or the number of syllables for each line. Common Metre, CM, is 8 6 8 6.

My current favourite tune is “Sweet Chiming Bells”, which I have found in the Voiceworks Folk (OUP) Anthology.

Here’s a simple arrangement for SAB:

The carol has an interesting history – Wikipedia and www.hymnary.org are good starting points, and will no doubt lead you hither and thither across the internet.