Francis I Stephen

The house of Habsburg-Lorraine descends from Francis Stephen, the Lorraine duke whose marriage to Maria Theresa in 1736 carried the Habsburg inheritance into a new male line. Born at Nancy in 1708, he was the son of Duke Leopold of Lorraine and Élisabeth Charlotte d'Orléans, a niece of Louis XIV, which made Francis a great-grandson in the female line of the Bourbon kings of France even as he was raised, from his teens, at the Habsburg court in Vienna, where Emperor Charles VI groomed him as a prospective son-in-law.

Dynastic geography exacted a price for the marriage. In the settlement ending the War of the Polish Succession, France insisted that Lorraine pass to Stanisław Leszczyński and ultimately to the French crown; Francis surrendered his ancestral duchy and received in compensation the Grand Duchy of Tuscany, which he inherited on the death of the last Medici grand duke in 1737. He married Maria Theresa in Vienna in February 1736, and when Charles VI died in 1740 she became ruler of the Habsburg lands with Francis as co-regent.

The imperial title, which could not pass to a woman, slipped from the dynasty in 1742, when the Wittelsbach elector Charles Albert of Bavaria was elected emperor as Charles VII during the War of the Austrian Succession. After Charles VII's death, Francis was elected Holy Roman Emperor in 1745, restoring the crown to Vienna. Political direction nonetheless remained largely with Maria Theresa in her own hereditary lands; Francis applied himself with marked success to finance and enterprise, reorganizing the family's resources and amassing a private fortune that became the basis of the Habsburg family fund. He also collected natural history specimens and coins, collections that later seeded Vienna's imperial museums.

The marriage was, by dynastic standards, close and exceptionally fruitful: sixteen children, among them the future emperors Joseph II and Leopold II, and Marie Antoinette, whose marriage to the future Louis XVI of France sealed the Austro-Bourbon alliance of 1756. Francis died suddenly at Innsbruck in August 1765, during the wedding festivities of his son Leopold. Maria Theresa wore mourning for the rest of her life; their descendants ruled in Vienna until 1918.