Frances Villiers, Countess of Jersey his "wife", Maria Fitzherbert, with whom he had undergone a form of marriage in a clandestine Church of England ceremony that all parties to it knew was invalid under the Royal Marriages Act 1772. Having encouraged the Prince of Wales to marry his first cousin, Caroline of Brunswick in 1794, Lady Jersey nevertheless set out to make Caroline's life difficult. However, the now Princess of Wales (Caroline) had very little regard for George IV, nor he for her, and after the birth of their child, they lived apart during their twenty-five year marriage, leaving a void Frances and other mistresses,
Frances Robinson-Duff teaching career in Paris, and during World War I, she volunteered her services to teach wounded soldiers how to regain the use of damaged lungs. Shortly after the end of the war, mother and daughter moved to New York City, where Frances established herself as a leading voice teacher, whose many famous pupils included Mary McCormic, Dorothy Gish, Helen Hayes, Kenneth MacKenna, Catherine Calvert, Ina Claire, Miriam Hopkins, Ruth Chatterton, Mary Pickford, Clark Gable, Norma Shearer, and Katharine Hepburn. The Robinson-Duff approach to voice training involved elaborate vocal and breathing exercises focused on the use of the diaphragm, a method