Elisabeth (Elisabeth Amalie Eugenie; German: [eˈliːzaˌbɛt aˈmaːliə ɔʏˈɡeːniə]; 24 December 1837 – 10 September 1898), nicknamed Sisi, was Empress of Austria and Queen of Hungary from her marriage to Franz Joseph I on 24 April 1854 until her assassination in 1898. Elisabeth was born into the Bavarian House of Wittelsbach but enjoyed an informal upbringing before marrying her first cousin, Emperor Franz Joseph I, at 16. The marriage thrust her into the much more formal Habsburg court life, for which she was unprepared and which she found suffocating. The couple had four children: Sophie, Gisela, Rudolf, and Marie Valerie. Early in her marriage, Elisabeth was at odds with her aunt and mother-in-law, Archduchess Sophie, who took over the rearing of Elisabeth's children. The birth of a son, Rudolf, improved Elisabeth's standing at court, but her health suffered under the strain. As a result, she would often visit Hungary for its more relaxed environment. She came to develop a deep kinship with Hungary and helped to bring about the dual monarchy of Austria-Hungary in 1867. The death of Crown Prince Rudolf and his mistress Baroness Mary Vetsera in a murder–suicide at his hunting lodge at Mayerling in 1889 was a blow from which Elisabeth never fully recovered. She withdrew from court duties and travelled widely, unaccompanied by her family. In 1890, she had the palace Achilleion, named after the Greek hero Achilles, built on the Greek island of Corfu. The palace featured an elaborate Greek mythological motif and served as a refuge, which Elisabeth visited often. She was obsessively concerned with maintaining her youthful figure and beauty, developing a restrictive diet and wearing extremely tightlaced corsets to keep her waist looking very small. While travelling in Geneva in 1898, Elisabeth was fatally stabbed in the heart by an Italian anarchist named Luigi Lucheni. Her tenure of 44 years was the longest of any Austrian empress.