FRANCIS I. (1708-1765), Roman emperor and grand duke of Tuscany, second son of Leopold Joseph, duke of Lorraine, and his wife Elizabeth Charlotte, daughter of Philip, duke of Orleans, was born on the 8th of December 1708. He was connected with the Habsburgs through his grandmother Eleanore, daughter of the emperor Ferdinand III., and wife of Charles Leopold of Lorraine. The emperor Charles VI. favoured the family, who, besides being his cousins, had served the house of Austria with distinction. He had designed to marry his daughter Maria Theresa to Clement, the elder brother of Francis. On the death of Clement he adopted the younger brother as her husband. Francis was brought up at Vienna with Maria Theresa on the understanding that they were to be married, and a real affection arose between them. At the age of fifteen, when he was brought to Vienna, he was established in the Silesian duchy of Teschen, which had been mediatized and granted to his father by the emperor in 1722. He succeeded his father as duke of Lorraine in 1729, but the emperor, at the end of the Polish War of Succession, desiring to compensate his candidate Stanislaus Leszczynski for the loss of his crown in 1735, persuaded Francis to exchange Lorraine for the reversion of the grand duchy of Tuscany. On the 12th of February 1736 he was married to Maria Theresa, and they went for a short time to Florence, when he succeeded to the grand duchy in 1737 on the death of John Gaston, the last of the ruling house of Medici. His wife secured his election to the Empire on the 13th of September 1745, in succession to Charles VII., and she made him co-regent of her hereditary dominions. Francis was well content to leave the reality of power to his able wife. He had a natural fund of good sense and some business capacity, and was a useful assistant to Maria Theresa in the laborious task of governing the complicated Austrian dominions, but his functions appear to have been of a purely secretarial character. He died suddenly in his carriage while returning from the opera at Innsbruck on the 18th of August 1765. See A. von Arneth, _Geschichte Maria Theresias_ (Vienna, 1863-1879).