This is a traditional Irish Slip Jig. The earliest publication of the tune that I am aware of was in 1804 in "National Irish Music" by O'Farrell under the title 'Welcome to Limerick' in which O'Farrell claimed it as an original composition. Other popular names for the tune include 'The Choice Wife' -- a name it was performed under by the piper Willie Clancy, and the often chortle inducing Irish Title 'An Phis Fliuch". Anyway, it's one of my favorite tunes. The first 40 seconds of intro here is not part of the traditional tune, its just me trying to get to the start.