OK, second try. Sorry if I'm repeating myself, but the first seems to have vanished.

The Bodleian Library at Oxford has a broadside of the words dated to "between 1846 and 1854."

Different lyrics in the same spirit appear in a garland called "The Entertaining Companion" dated to "ca1780" by The British Library.

The version generally sung at Ren Faires and on albums was evidently written by Oscar Brand in the 1950s from a traditional version sung in Scots by Jeannie Robertson.