Archduchess Sophie of Austria (German: Sophie, Erzherzogin von Österreich; 5 March 1855 – 29 May 1857) was the first child and first of three daughters born to the Empress Elisabeth (Sissi) and Franz Joseph, Emperor of Austria. She died aged two.

Within two months of the marriage, Elisabeth was obviously pregnant. On 5 March 1855, the soon-to-be eighteen-year-old Empress of Austria delivered a daughter who was christened the same day Sophie Friederike Dorothea Maria Josepha, after Franz Joseph's mother. The infant was christened such without Elisabeth even knowing. On both her mother and her father's side, Sophie descended from King Maximilian I Joseph of Bavaria, as her parents were first cousins. On her father's side, she descended from the last Holy Roman Emperor, Francis II. During the next year, Elisabeth presented Franz Joseph with another daughter, Archduchess Gisela, a younger sister to Sophie. Even though they were both girls and did not need to be educated for duties a monarch would be obliged to fulfil, both infants right after being baptised were taken away from Elisabeth by Princess Sophie of Bavaria (who was both Elisabeth's aunt and mother-in-law) on account of the Empress being too young to raise two children. Elisabeth later commented:

No matter how long Elisabeth begged Franz Joseph to discuss the matter with his mother, her cries went unheard. Eventually, Franz Joseph did discuss the problem with his mother and Elisabeth eventually began to openly express her wishes to her mother-in-law and even took the little girls with her as she travelled.

Empress Elisabeth adored Hungary and its people and proposed to her husband that they take a trip to her favourite country, perhaps even tour it. This was a desire she would regret for the rest of her life. Franz Joseph accepted and they left in early spring 1857. While in Budapest, both Sophie and her sister Archduchess Gisela fell ill with diarrhea and had a very high fever. Ten-month-old Gisela recovered quickly. However, two-year-old Sophie's body could not take it. At 21:15 in the evening, after eleven hours of struggling to survive, Sophie died in her mother's arms, probably from dehydration due to the diarrhea or from convulsions due to the high fever. It was later theorized that Sophie died from typhus fever, but this is yet to be proven.

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