 On her mother's death Lady Katherine's elder sister, Lady Rosamund Agnes (1914–2003) became the 11th Countess of Dysart, but never married or had issue, on her death in December 2003 Lady Katherine succeeded to the titles of Countess of Dysart and Lady Huntingtower.Under the Scottish peerage tradition, it is a title that goes to an eldest daughter if there is no male child.It has moved from earl to countess for centuries.