 Elizabeth Angela Marguerite Bowes @-@ Lyon was the youngest daughter and the ninth of ten children of Claude Bowes @-@ Lyon , Lord Glamis ( later the 14th Earl of Strathmore and Kinghorne in the Peerage of Scotland ) , and his wife , Cecilia Cavendish @-@ Bentinck . Her mother was descended from British Prime Minister William Cavendish @-@ Bentinck , 3rd Duke of Portland , and Governor @-@ General of India Richard Wellesley , 1st Marquess Wellesley , who was the elder brother of another Prime Minister , Arthur Wellesley , 1st Duke of Wellington . 
