John, I may have gotten this from you several years back: "Clan Birn, descended from Bern, son of Ruadrí, son of Murchad, a quo Muinter Birn, in the line of Cenél Eóghain, according to the genealogies in Rawlinson B502. In addition Rawlinson points to a son of Bern named Anféid, a quo Tellach n-Anfida, who was possibly the namesake for Tellach Ainbhith. According to O'Dugan (Topographical Poems), the MacRuaidhris were among those over Teallach Ainbhith and over Muintir-Birn. O'Hart (Pedigrees) cites the name MacRuaidhri as MacRory or MacRogers, over the same territories, districts which he places in the baronies of Dungannon and Strabane, county Tyrone. Woulfe (Irish Names) agrees and also cites the family of MacRuaidhri as erenaghs of Ballynascreen, in County Derry. O'Hart goes on to cite, under the county Armagh, Muintir Birn, some of whose descendants anglicized their name Bruen, was a district in the south of the barony of Dungannon, adjoining the territory of Trough in county Monaghan. In Murphy surname history, there is mention of the surname Mac Murchadha (MacMurphy, Murphy), originally based in present-day Co. Tyrone, in the area known as Muintir Birn, but were driven out by the O'Neills and settled in south Armagh. The reference seems corroborated in various entries in the Annals, although the name Mac Murrough seems to be applied there, which may have later been translated into MacMorrow or MacMurray. In Colgan's Trias Thaumaturga, it mentions Ui Briuin, now Muinter Birn, alias Ui Briuinia Aquilonaris, in county Tír Eoguin, and diocese of Ardmache. This is an apparent reference to Ua mBriúin Archaille in Ui Chremthaind, a branch of Siol Colla dá Chrich, who were also noted in the Dungannon area." Of special interest to me is O'Hart's statement that some descendants anglicized their name to Bruen. I have eight M222 Byrne who are not close to my Donegal or Sligo M222s. Their roots are Monaghan, and I am wondering if they are remnants of that Muinter Birn/Cenel Eoghain group that you mentioned. Do the O Cathains have any distinctive markers, such as the 391=10 that separates this Monaghan Byrne group from my other M222s? Paul