Tom,

THat song is a translation of the Gaelic "Fáinne Geal an Lae", which means, as you might expect the dawning of the day - literally the Bright ring of Day. There is at least one other Dawning of the Day song to the same air which I have heard sung, but I don't know where the lyrics might be (The DT maight be a good starting point).

On a more general point I find it hard to believe that PK wrote Raglan road, which actually contains the phrase "The Dawning of the Day" without this air in mind. It has been said elsewhere that Kavanagh gave Luke Kelly the lyrics and Luke matched them to the tune, but as I say this doesn't make a lot of sense to me.