In 1377 on the death of Thomas Stewart, 3rd Earl of Angus, without issue, the title devolved on his sister, Lady Margaret. She resigned it in 1389 and King Robert II then granted the earldom ofAngus, with the lordships of Abernethy, in Perthshire, and of Bonkil, in Berwickshire, to George Douglas, her illegitimate son by William, 1st Earl of Douglas, her brother-in-law.
George Douglas, 1st Earl of Angus of the Douglas family, married the second daughter of King Robert III, was taken prisoner at the Battle of Homildon, in 1402, and died the same year in England of the plague.

Source: The Great Historic Families of Scotland, James Taylor, 1889.