Princess Isabella of Parma

Isabella of Bourbon-Parma (Spanish: Isabel María Luisa Antonieta, German: Isabella Maria Ludovica Antonia; 31 December 1741 – 27 November 1763) was a princess of Parma and infanta of Spain from the House of Bourbon-Parma as the daughter of Philip, Duke of Parma. She became an archduchess of Austria and crown princess of Bohemia and Hungary in 1760 by her marriage to Archduke Joseph of Austria, the future Joseph II, Holy Roman Emperor.

Although her husband loved her, she did not fully return his feelings and found more fulfillment in her (likely romantic, possibly sexual) relationship with her sister-in-law, Archduchess Maria Christina. An austere and lonely childhood, the sudden loss of her unaffectionate but beloved mother, an unhappy arranged marriage, a court life that did not fit her, and a difficult birth followed closely by two miscarriages and a fourth pregnancy all affected her mental health, leading to depression or bipolar disorder, to which she was likely genetically predisposed. She died at the age of twenty-one from smallpox.