Charles VI paved the way for her accession with the Pragmatic Sanction of 1713 and spent his entire reign securing it.
Charles VI died on 20 October 1740, probably of mushroom poisoning.
These plans were forestalled by his death from smallpox. Religious differences prevented him from arranging his daughter's marriage to the Calvinist prince Frederick of Prussia.
In 1725, he betrothed her to Charles of Spain and her sister, Maria Anna, to Philip of Spain.
By marriage, she was Duchess of Lorraine, Grand Duchess of Tuscany and Holy Roman Empress.
She started her 40-year reign when her father, Emperor Charles VI, died in October 1740.