Margaret Beaufort, Countess of Stafford British countess (1437-1474) (1437–1474) Parents Eleanor Beauchamp Edmund Beaufort, 2nd Duke of Somerset Children Margaret Dayrell Henry Stafford, 2nd Duke of Buckingham unknown Stafford Siblings Edmund Beaufort, 4th Duke of Somerset Eleanor Beaufort Henry Beaufort, 3rd Duke of Somerset Thomas de Ros, 9th Baron de Ros John Beaufort, Marquess of Dorset Richard Ros Mary Beaufort Margaret de Ros Anne Beaufort Elizabeth Beaufort Lady Joan Beaufort Thomas Beaufort Partners Sir Richard Dayrell Humphrey Stafford, Earl of Stafford