It was written by Peadar Kearney (1883-1942), lyricist of the Irish national anthem. Kearney fought in 1916 and knew what he was talking about, plus he was a great natural songwriter.                     

I haven't heard Dick's version, but no one will ever improve on Josh MacRae's 60s recording,in my opinion: sadly no longer available. I've got a good deal more, but must go now.