I'd always thought it was an old Irish tune, but I notice Sir Charles Forbes sometimes listed as the composer and also see it alternately titled as "Sir Charles Forbes of Edinglassie's Quickstep." Looking him up, we find he was anything but Irish, but his political career would have brought him some sympathies across the Irish Sea. The article doesn't mention anything about him being a musician. Maybe the tune was written in his honor.
https://en.wikipedia.org/wiki/Sir_Ch...s,_1st_Baronet