Martha Bruce, Countess of Elgin and Kincardine, born Martha White and known for most of her life as Lady Elgin, was the wife of Charles Bruce, 5th Earl of Elgin and 9th Earl of Kincardine, mother of the collector Thomas Bruce, 7th Earl of Elgin, and governess to Princess Charlotte of Wales, daughter of the future King George IV, at the time second in line to the throne. Wikipedia