Scottish noble prominent during the reigns of the Bruces Robert I and David II.

He gave refuge to Edward II of England after the Battle of Bannockburn and contrived his escape by sea to England. Later, he made peace with Robert de Bruce and by him was appointed governor of Berwick Castle, which he held against Edward III until the defeat of the Scots at Halidon Hill (July 19, 1333) made it no longer tenable. His countess, known in Scottish history and romance as “Black Agnes” (because of her swarthy complexion), daughter of Thomas Randolph, Earl of Moray, and grandniece of Robert de Bruce, is famous for her defense of Dunbar Castle against the English under the Earl of Salisbury in 1338, Salisbury being forced to abandon the attempt after a fierce siege lasting 19 weeks. The countess succeeded to the estates and titles of her brother, John Randolph, 3rd Earl of Moray. The earldom of Moray passed after her death to her second son, John Dunbar. The earldoms of March and Dunbar passed to a cousin of the 2nd earl, George Dunbar.