A.L. Lloyd pointed out that Farquhar's play, 'The Recruiting Sergeant' (1706) helped popularise 'Over the Hills and Far Away'. The song was often sung during the Napoleonic Wars. It 'survived for two and a half centuries among folk singers, dwindling all the time, till it seemed to be limited to the Scottish north-east'. Then a variant came back into 'vigorous circulation in English cities under the title "Two Recruiting Sergeants from the Black Watch"'. ['Folksong in England' Paladin 1975 pp 237-238].

--Stewie.