http://hal_macgregor.tripod.com/gregor/IrishPicts.html 

My friend Ruairí Ó Bléine writes: “This site is most interesting and informative. I have seen two items that need correction. The word “Uladh” is the genitive of “Ulaidh”. For example we say Cúige Uladh – the province of Ulster, but Ulaidh Abú – Hurrah for Ulster. The other problem is that Firbolg is already in the plural and does not need to have an “s” added for Fir is Men and  Bolg is a version of Belgae.”