Actually there is an all-Irish language version of 'An Cruiscin Lan'(sorry about the absence of the 'fada'). The song features on a collection of songs by the late great Nioclas Toibin, called Rinn na nGael.

I've heard it said that it was a drinking song of The Irish Brigades in the armies of various European 'anciens regimes'in the 17th and 18th centuries.