What about the song in Sam Henry's collection ? It has a lovely tune , but after the opening verse (below from memory) becomes very fanciful . I don't know if it has ever been recorded.

Belfast Town now rich and great
was then a village small
And flocks of sheep grazed on the spot
where stands the Linen Hall
And at that time young Dermot lived
and a collar of gold he wore
He ruled the ground from Belfast Town
to the Mourne Mountain shore