Edited sentence: At the age of 15, when he was brought to Vienna, he was established in the Silesian Duchy of Cieszyn, which had been mediatized and granted to his father by the emperor in 1722.Emperor Charles VI favored the family, who, besides being his cousins, had served the house of Austria with distinction.Francis was brought up in Vienna with Maria Theresa on the understanding that they were to be married, and a real affection arose between them.He had designed to marry his daughter Maria Theresa to Francis' older brother Clement.He succeeded his father as Duke of Lorraine in 1729, but the emperor, at the end of the War of the Polish Succession, agreed to compensate the French candidate Stanislaus Leszczynski for the loss of his crown in 1735 and persuaded Francis to exchange Lorraine for the Grand Duchy of Tuscany.He was born in Nancy, Lorraine (now in France), the oldest surviving son of Leopold Joseph, duke of Lorraine, and his wife Elizabeth Charlotte, daughter of Philippe I, duc d'Orléans and Elizabeth Charlotte, Princess Palatine.He was connected with the Habsburgs through his grandmother Eleanore, daughter of Emperor Ferdinand III, and wife of Charles Leopold of Lorraine, his grandfather.On Clement's death, Charles adopted the younger brother as his future son-in-law