Princess Stephanie of Windisch-Graetz's mother was a member of what political party?
Archduchess Elisabeth Marie of Austria Archduchess Elisabeth Marie of Austria (Elisabeth Maria Henriette Stephanie Gisela; 2 September 1883 – 16 March 1963) was the only child of Rudolf, Crown Prince of Austria and Princess Stéphanie of Belgium, and a granddaughter of Emperor Franz Joseph I of Austria and King Leopold II of the Belgians. She was known to the family as "Erzsi", a diminutive of her name in Hungarian. Later nicknamed "The Red Archduchess", she was famous for becoming a socialist and a member of the Austrian Social Democratic Party.
Caroline, Princess of Hanover Caroline, Princess of Hanover (Caroline Louise Marguerite Grimaldi; born 23 January 1957), is the eldest child of Rainier III, Prince of Monaco, and American actress Grace Kelly. She is the elder sister of Prince Albert II and Princess Stéphanie. Until the births of her niece and nephew Princess Gabriella and Prince Jacques of Monaco in December 2014 she had been heir presumptive to the throne of Monaco since 2005, a position which she previously held from 1957 to 1958.