Margaret Beaufort (1443-1509), mother of Henry VII, and by her marriage to Thomas Stanley, first Earl of Derby, Countess of Richmond and Derby.

Her Manx significance is her husband's. The Island was his, and the Manx writers who mention her do so in passing, as the mother whose son's crown followed from Richard III's designs on the Stanleys. The standard nineteenth-century life of her, Caroline Halstead's of 1839, mentions the Island only casually, at three pages of the whole book, and the Manx bibliographers note the fact when they list it.