Y Gwr a'i Farch ( The Man and his Horse)comes from Edward Jones' Musical and Poetic Relicks of the Welsh Bards(1784), where it was given as a dance for five people. A perfect tune forWelsh Bagpipes. It can also be played as a round.
There is a recording of the tune available.Calennig:- Songs and Tunes from Wales GVRCD214. There, it is played on two Anglo Concertinas.