The arms are those of Macdonald impaling Montgomerie, for Lady Margaret Macdonald (d. 1799). Famed for her loveliness, Lady Margaret was the daughter of Alexander, 9th Earl of Eglinton (d. 1729), and was married to Sir Alexander Macdonald (1711-1746), 7th baronet and 14th Chief of Sleat. She and her husband lived at Monkstadt house, the seat of the clan Donald on the Isle of Skye. Although Sir Alexander initially claimed to favor the Stuart restoration, he refused to join the Young Pretender after he landed in Scotland in 1745, and instead sided with the government. However, Lady Margaret remained sympathetic to the Jacobite cause, secretly sending clothes, newspapers, and money to the fugitive Bonnie Prince Charlie. The Prince sent Lady Margaret a letter expressing his gratitude, but, to her lasting regret, she was forced to burn it when her home was searched by government forces.
Lady Margaret was greatly beloved; when James Boswell and Samuel Johnson visited Skye in 1773, they were told that "when she travelled through the island, the people ran in crowds before her, and took the stones off the road, lest her horse should stumble and she be hurt." (J. Boswell, The Journal of a Tour of the Hebrides, vol. II, 1898, p. 20.) Her name also lives on in a traditional Scottish bagpipe tune, "Lady Margaret Macdonald's Salute."