His father's wife Margaret had already produced an heir for her Lord in 1358, James, 2nd Earl of Douglas and Mar, who succeeded his father upon his death in 1384.
In 1389, Margaret of Angus relinquished her title in favour of her son, but George did not assume it until his betrothal in 1397 to Princess Mary Stewart, daughter of King Robert III of Scotland. The influence of George's mother must have been considerable - in addition to obtaining a royal bride for George, she persuaded King Robert III to confirm him in his style of Earl of Angus, and also to bestow upon him the lordships of Abernethy, (Perthshire) and Bonkill, (Berwickshire); and "to endow him and his spouse with the justiciary fees of the County of Forfar, to ratify all gifts, entails, and leases made or to be made by his half-sister, Isabel, Countess of Mar, to the said Jorge her brothir".[1]
Lady Elizabeth Douglas, married firstly to Sir Alexander Forbes, later 1st Lord Forbes; married secondly to Sir David Hay of Yester.
Mary was to marry a further four times and bear seven more children by three of these husbands. The issue by her second husband, Sir James Kennedy the Younger of Dunure, were the ancestors of the Marquesses of Ailsa; The product of her fourth marriage to William, 1st Lord Graham were the ancestors of the Viscounts of Dundee and the Dukes of Montrose.
References
^Maxwell, Sir Herbert.A History of the House of Douglas. Freemantle, London 1902