Anne Scott was the younger daughter of Francis, 2nd Earl of Buccleuch, and succeeded her elder sister, Mary, in 1661, as 4th Countess in her own right. She married, in 1663, James Crofts, Duke of Monmouth, the illegitimate son of Charles II, who assumed the surname Scott before the marriage. They were created Duke and Duchess of Buccleuch, and when the Duke was executed for high treason on the 15 July 1685, though his honours were forfeit, those enjoyed by the Duchess in her own right, including the Dukedom of Buccleuch and the Earldom of Dalkeith, were unaffected. By the Duke of Monmouth she had several children. The eldest son was styled Earl of Doncaster, but dying in infancy, the second son assumed the courtesy title, and after his father's attainder was styled Earl of Dalkeith in right of his mother. On her death his eldest son became 2nd Duke of Buccleuch. The Duchess married secondly, in 1688, Charles, 3rd Lord Cornwallis, but they had no surviving issue. Duplicates from the Buccleuch library were sold at Sotheby, Wilkinson & Hodge on the 25 March 1889, and a further part of the library at Sotheby & Co's Hodgson's Rooms 17 March 1971.