In 1514 Archibald Douglas, 6th Earl of Angus, was privately married to Margaret, the Queen Dowager of Scotland, following the death of her husband, James IV. However, the marriage was a failure and they were divorced in 1527, although Douglas acted as Regent to James V until 1528. He died at Tantallon Castle, East Lothian, in 1557.

When the narrative of his life is impartially followed, what is most conspicuous is that his talents were improved by experience and that his character was strengthened by adversity. The young and handsome courtier who showed little capacity for business, and timidity, is not lack of courage, in action, acquired skill in the management of men and affairs, and became an able and brave commander.
- Dictionary of National Biography.

Additional Information on
Archibald Douglas, 6th Earl of Angus (1489-1557)

Douglas was a powerful Scottish lord whose marriage to Margaret Tudor in 1514 was encouraged by Henry VIII but which had the effect of infuriating the Scottish nobles who then forced Margaret to resign as Regent for the infant James V in favour of the Duke of Albany and flee to England. When Margaret returned she found that Douglas had taken up with the daughter of a laird, and so she combined with Albany to throw him out, accusing him of treason. Douglas was packed off to France in 1522 but with the support of Henry VIII he returned in 1525 and called parliament together.

For the next three years Douglas was in control but Margaret retaliated by divorcing him in 1528, and when James decreed that his estates be confiscated, he fled to England. James revenged himself on Douglas' relations by having his sister burnt at the stake. When he again returned to Scotland in 1542, after the death of James V, Douglas had his estates returned to him and was even required to arrange the marriage of Mary Queen of Scots to the future Edward VI, but without success.