About Archduchess Elisabeth Marie of Austria
Archduchess Elisabeth Marie Henriette Stephanie Gisela of Austria (Hungarian: Erzsébet Mária Henrietta Stefánia Gizella; 2 September 1883 – 16 March 1963) was the only child of Rudolf, Crown Prince of Austria, and Princess Stéphanie of Belgium. Her father was the son and heir apparent of Emperor Franz Joseph I of Austria, and her mother was a daughter of King Leopold II of Belgium. She was known to her family as "Erzsi", a diminutive of her name Erzsébet in Hungarian. Later nicknamed The Red Archduchess, she was famous for becoming a socialist and a member of the Austrian Social Democratic Party. == Early life == Archduchess Elisabeth (nicknamed 'Erzsi' – the abbreviation of the Hungarian version of her first name Erzsébet) was born at Schloss Laxenburg on 2 September 1883 to Crown Prince Rudolf and Stéphanie, daughter of King Leopold II of Belgium. She was named after her grandmothers, Empress Elisabeth of Austria and Queen Marie Henriette of Belgium. Erzsi was Franz Joseph's only grandchild through his son. In 1889, when Erzsi was a little over five years old, her father and Baroness Mary von Vetsera, his mistress, were found dead in what was assumed to be a murder-suicide pact at the Imperial hunting lodge at Mayerling. Her father's death interrupted the dynastic succession within the Austrian imperial family, fractured her grandparents' already tenuous marriage and was a catalyst in Austria-Hungary's gradual destabilization, which culminated in the First World War and the subsequent disintegration of the Habsburg Empire. After Rudolf's death, Franz Joseph took over guardianship of Erzsi; by his order, she was forbidden to leave Austria with her mother.
Biography source: Wikipedia. The profile adds birthday-specific historical context from the Celebs Birthday Today editorial database.