Katherine Wellesley-Pole, Countess of Mornington British noblewoman (1765–1851) Parents Lady Mary Capell John Forbes Children Priscilla Fane, Countess of Westmorland William Pole-Tylney-Long-Wellesley, 4th Earl of Mornington Mary Wellesley-Pole Lady Emily Wellesley-Pole Siblings Maria Eleanor Forbes Partners William Wellesley-Pole, 3rd Earl of Mornington