About Alexander Gordon of Strathavon
From Darryl Lundy's Peerage page on Alexander Gordon of Strathavon:
Alexander Gordon of Strathavon 
- M, #329433
- Last Edited=25 Apr 2011
- Consanguinity Index=0.78%
Alexander Gordon of Strathavon is the son of Alexander Gordon, 3rd Earl of Huntly and Lady Jean Stewart.
He was ancestor of the Gordons of Cluny.
- 1. [S37] Charles Mosley, editor, Burke's Peerage, Baronetage & Knightage, 107th edition, 3 volumes (Wilmington, Delaware, U.S.A.: Burke's Peerage (Genealogical Books) Ltd, 2003), volume 2, page 2012. Hereinafter cited as Burke's Peerage and Baronetage, 107th edition.
From the English Wikipedia page on the Gordon Baronets:
Gordon of Cluny, Aberdeen (1625)
- Sir Alexander Gordon, 1st Baronet (d. c. 1648)
- Sir John Gordon, 2nd Baronet (d. c. 1668)
- baronetcy dormant c 1668
From Gordon DNA Project
m. The youngest daughter of John Grant of Grant, by whom he had four daughters and two sons:
1. Alexander d. young, leaving one daughter 2. John - succeeded to Cluny, and was the ancestor of the families of Cluny, Birsmoir, Pittendreich, and others
The family of Cluny was one of the first to receive the new dignity of a Baronetcy, but it was only held for two generations and became extinct about 1650. Cluny has been subsequently owned by two other families of Gordons, one a branch of the Sutherland Gordons, and another of unknown lineage.
The house of Birsmoir was one of those which lost their lands in consequence of the wars of the covenant.
The representative of the family was Governor of Pennsylvania in America in the 18th c and his descendants were in existence about 1840.
In addition to this family, Alexander had also two natural sons:
1. William Gordon, of Delmore, and ancestor of the Croughly Family 2. George Gordon of Tombae, ancestor of the families of Tombae and Auchdregnie
These two sons were granted the rights and privileges of legitimate birth by a charter issued under the great seal of Scotland, at Perth, on the 24th June, 1553. Their mother's name has not been preserved but it appears most probable that they were the issue of a union peculiar to Scotland, known as "Handfasting." This custom had long prevailed among the Highlanders, and was merely a formal betrothal, which might at any subsequent time be made a marriage, valid from the date of the preliminary ceremony; or the couple might separate when they pleased. The existing law in Scotland [at the time of publication in 1895], by which a marriage legitimises any previous offspring between the couple, is probably a survival of this practice. Handfasting soon became extinct following a proclamation issued in December 1562 by the Kirk Session of Aberdeen outlawing the practice.
Alexander Gordon of Strathavon's Timeline
Probably Huntly, Aberdeenshire, Scotland, (Present UK)
Strathdon, Aberdeenshire, Scotland
Probably Strathoun, Inverness, Scotland, (Present UK)