Maria Theresa's father was Charles VI. She inherited her throne from him because she was the eldest sibling
Maria used a legal technicality to make her husband Francis Stephen co-ruler of Austria and Bohemia so that he could later be eligible for the title of Holy Roman Emperor. Because she was female, Maria Theresa could never officially hold the title of Holy Roman Emperor.
Charles Albert of Bavaria successfully invaded and conquered several portions of Maria's empire. On January 24, 1742, Charles Albert was elected as the Holy Roman Emperor, denying Maria's husband a chance at the title.
Maria's forces had made significant advances in regaining her lost territory. Maria was crowned Queen of Bohemia, just a year after losing the territory to Charles Albert of Bavaria.
Maria's husband Francis died on the same weekend that their son Leopold was celebrating his marriage. Maria's son Joseph immediately became the Holy Roman Emperor but would rule as her co-reg
Maria fell ill and a week later, she was pronounced dead by her personal physician. After her death she is still famous for the reform in the government and military.