Francis I (1708-1765) succeeded his father Duke Leopold Joseph Charles as Duke of Lorraine and Bar in 1729, Viceroy of Hungary in 1732, renounced the Duchies of of Lorraine and Bar in 1736 but succeeded in accordance with the terms of of the Treaty of Vienna (1735) as Grand Duke of Tuscany on the death of the last Medici Grand Duke Gian Gastone in 1737, elected Emperor on 13 September 1745. He married Maria Theresia, Queen of Hungria and Bohemia (1717-1780) in 1736