The song is Mairi's Wedding, also known as the Lewis Bridal Song. John Loesberg writes in his "Traditional Folksongs and Ballads of Scotland," vol. 3, that it was "a traditional tune taken down by Dr. Peter MacLeod (1797-1859) who published four volumes of Scottish songs." Evidently it was issued with new words by Hugh Roberton (1874-1952).

Here are the words I learned:

(chorus) Step we gaily, on we go
Heel for heel and toe for toe
Arm in arm and row on row
All for Mairi's wedding

(verse 1)
Over hill ways up and down
Myrtle green and bracken brown
Past the shielings, through the town
All for sake of Mairi.

(chorus)

(verse 2)
Red her cheeks as rowans are,
Bright her eye as any star,
Fairest of them all by far
Is our darling Mairi.

Chorus

(verse 3)
Plenty herring, plenty meal,
Plenty peat to fill her creel
Plenty bonny bairns as weel;
That's the toast for Mairi.

Chorus

+++++ My father used to sing this; I don't know when he learned it. He had an old record called "Scottish Sing-Alongs" that included the song, and he'd always tell me that I would have the song at my wedding. He died a few years ago, but if and when I get married, I will definitely hire a piper to come play it--and I want all the guests to sing along.

I'd bet you could find a recording of the song without too much trouble. Good luck -

Liz