Excellent thread and very informative.
Weiss also provided the tune to Longfellow's 'The Village Blacksmith'.
1855.
I have a copy of MacKay's 'Ballads and Lyrics' published in 1859, but all of the collected material within predates the 'Rolling Home' publication.
An original set of words appears on a broadside at Bodleian Firth c16 (386) website.

Something disturbs me from the earliest postings on this thread. There is a suggestion that because we know who wrote it it can't be traditional. Surely no-one still follows this pointless dogma!