The proposed Origin of The Grahams | Toponymy | Forum

Hello Bruce,

It would appear that there are many assumptions underlying your post which should break down under examination.
First: bear in mind that surnames are in essence affectation and the great majority of bearers of almost all clan surnames bear no blood relationship with the chiefly lines - so there is no problem at all with your apparent DNA anomalies. And so no... the vast bulk of you did NOT 'start off' from William de Grahame. However it would be well for you to start from the assumption that the "de" indicates that what follows is likely to be geographical.
Second: As for "Graham's Dyke" Scottish history is littered with examples of fantastic claims to antiquity. Even let us suppose that someone called Grim breached the Antonine Wall at some time (this was happening all the time so it is no big deal) the problem is that there were no surnames at that time and so any connection is at best serendipitous
Third: There have been major changes in pronunciation (think water and daughter for example).
Fourth: Let's break Grantham down. You focus on the "th" - but this is problematic, for really it is Grant-ham - the hamlet on the gravel. So the development of the spoken "th" is a sophomore-style mistake by people who READ the name - and that mistake has become the accepted norm. However it is precisely the disjunction between these two original parts which would stimulate the loss of the middle altogether. [However you may be aware that Black says that Graham derives from a Grey-ham in Domesday Book.]
Fifth: so far as I understand it the earliest lands held by Grahams were around Abercorn and Dalkeith - a bit problematic for a Pict! But many incomers to the Highlands felt the need to fabricate a Pictish origin to fit in with the natives. [And think of that magnificent pile of rubbish which is the so-called (by Skene) Manuscript 1467 - now definitively demonstrated to be a concoction deriving from just about Skene's date for it.]

While the adoption of surnames amongst the aristocracy proceeded gradually from c1095, for the 'ordinary clansmen' adoption of this style was some centuries later and was for a long time less than firmly set - witness the Boll o' meal Frasers, the Trochie Grants and the way surnames have been adopted by males marrying a clan heiress etc.

Recommended reading: "Scottish Clans: Legend, Logic and Evidence"