Alwyn, 2nd Earl of Lennox (d by 1225)
m. Eva of Menteith (dau of Gilchrist, 1st Earl of Menteith)
Notes from http://www.clangalbraith.org/GalbraithsOfTheLennox/lennox.htm
GALBRAITHS OF THE LENNOX
PRIVATELY PRINTED
Compiled by Col. T. L. Galloway of Auchendrane in 1944
......It was in the old Cumbrian, or Clydesdale Kingdom, that the Earldom of Levenax was situated. Roughly, the boundaries were from the Clyde at Dumbarton to Arrochar in the North, and from the shores of the Gareloch to Fintry, including Kilpatrick and Baldernock. Loch Lomond and the banks of the Leven may be taken as the centre of the Earldom. It is here, then, in this interesting and beautiful part of Scotland that we can first trace the origin of the name "Galbraith."
The first Galbraiths who can be definitely found mentioned in any charter were the brothers Gillespie and Roderick Galbraith.
As witnesses in several charters they are called the nephews of Alwyn II, Earl of Lennox. Now, these brothers might be called nephews of Alwyn from various circumstances. They might be the sons of a brother of Alwyn. That Alwyn the first Earl had another son, Eth, is indicated in an Ayrshire Charter, dated 1193. (Liber de Melrose vol. I, p. 22.) But it would seem unlikely that sons of this Eth would be named Galbraith, and there is no evidence to show that he left any children.
Again the brothers might be sons of a daughter of Alwyn I and sister of Alwyn II married to a Galbraith. Or, again, Alwyn II might have married a lady of the Galbraith family, and Gillespie and Roderick be sons of a brother of that Countess.
Whichever way we take it, this seems certain, that the Galbraiths were of the old Lennox inhabitants and that they early intermarried with the family of Alwyn the 1st Earl of Lennox.