Quote Originally Posted by slohairt View Post
Irish names occurring in Scotland actually come from two sources: 1) As the bulk of Gaelic surnames are patronymics, it is highly probable that two unrelated surnames would appear in both countries at the same time. Though based on the same male personal name they are, in fact, not connected. The Scotii stopped migrating to Scotland long before the 'surname period' in Ireland occurred. (Reputed to be in the reign of Brian Boru.) 2) Irish emigration to Scotland occurring during the middle of the 19th Century. By the 1850s, a large bulk of the working-class in Glasgow were Irish. Their descendants are still numerous today. Scottish surnames occurring In Ireland: Lowland Scots (and some English) did migrate en masse to Ulster commencing in the 17th Century. Indeed, many names of non-Irish origin can be found all over Ireland. However, a source of Scottish (Gaelic) surnames in the North is often overlooked: Gallowglass. Many Highlanders fought for the Uí Néill and the Uí Dónaill. These soldiers-of-fortune were often granted land as payment. These individuals/families were easily assimilated into the native Irish population.
Whilst I agree that the Scotii emigrated to Scotland before surnames as such, I don't know that it was before clan names. That is, someone may have been known by only one name, with no separate first and last names, but he was a member of a particular clan. Of course, the members of the clan were not all genetically related though. IOW, even if it's the same clan in both Ireland and Scotland, and I think in some cases you can show that it is, it needn't imply actual descent, or at least not for the whole clan, although probably for the chiefs. When surnames came into use in Ireland, most would have taken the name of their clan, whatever genetic relationship existed to the founder of the clan, including none atall, and most wouldn't have actually known their family tree. Mainly just the chiefs would have been able to trace their lineage back. Of course, this means that the likelihood is that I'm not descended from the original Callaghan atall, but neither do I know that I'm not. It is interesting that in Scotland you have so many surnames that are septs of clans. I think this shows, to the extent that it is genuine and not invented, that clans continued to be important in Scotland long after the adoption of surnames, which is apparently not the case in Ireland. In both places you had many unrelated clan members, but in Ireland they tended to wind up with the clan surname. Point taken, though.