Song and tune were credited to a Pattie Birnie in an elegy on the latter by Allan Ramsay, 1721, and song and tune have been put as early as 1660. Whether that title represented the song and tune now known by this title seems doubtfull to me, however. The tune is first found in Aird's 'Airs', II, 1782, and the song seems to be first found (without music) in 'The Scots Nightingale', 1779, where the song is attributed to a Mr. Watts (but one attribution in this work is off by about 1 1/2 centuries). Murray on Saltspring can probably add to, or, correct this.