While married she bore the titles Princess of Wales , Duchess of Cornwall , Duchess of Rothesay , Countess of Chester and Baroness of Renfrew .
Diana 's full title , once divorced , was Lady Diana Mountbatten-Windsor , Princess of Wales and Countess of Chester , Duchess of Cornwall , Duchess of Rothesay , Countess of Carrick , Baroness of Renfrew , Lady of the Isles , Princess of Scotland .