Having the DUP in Killarney is a historic occasion in itself
The Duke, in this case, was not a reincarnated John Wayne, but Philip who's related to the Windsors by marriage, and famous for making faux pas while abroad, and the odd one at home, as well.
Oddly enough, the visit by Queen Elizabeth's husband, apart from the obvious speculation that she'll show the same good taste and come pony trekking here soon, wasn't quite as historic as that by the DUP.