In a message dated 8/27/2011 8:10:47 P.M. Central Daylight Time, rreid002@insight.rr.com writes: Such a beginning is found in the old Irish annals and the old writ, Ceart Ui Neill, out of Donegal, Ireland. The MacTavishes come from the Cenel nDuach a branch of the Cenel Conaill, descended from the Pictish Kings of Ros Guill and Irguill, now part of Donegal, and also from Dal-araidhe, now part of Antrim and Down. The Greek (Roman)historian, mapmaker and mathmetician, Ptolemy, mentions the tribe under the name of Ouenniknoi (Windukatii), and the lineage is tracable in such texts as the Irish Annuls of Ulster and Four Masters. This writer seems to be combining Lacey's Cruithin origin for the Cenel Conaill with his own guesses at the origin of his Scottish surname. The Ceart Ui Neill, the Rights of O'Neill mentions a sub-chieftain of the O'Donnells as Mac Giolla Shamhais from Ros Buill. The same name also appears in the Topographical Poems. To MacGillatsamhais the stout, Belong Ros-Guill2 and Ros-Iorguil,I reckon; O'Donovan's notes: 210. Gillatsamhais.-This name is now either unknown or lurks under some anglicised form. The most analogical anglicised form of it would be MacIltavish. The line is only traceable if you assume they are indeed descended from the Cenel Duach of Donegal. The pedigree of the Cenel Duach can be found in the Rawlinson B.502 genealogies and is as presented by the writer except for the inclusion of Fergus Cennfoda (or maybe that's something he took from Lacey or an entry in the Annals of Ulster in 586). Of course each name in the pedigree is a prince - one even married a daughter of King Loarn of Scotland. They held some early importance within the Cenel Conaill. One was King of Tara in the late 500s. At any rate it seems to be a classic example of someone latching onto an Irish surname in early records and assuming that is the origin of their own surname centuries later in another country. John