Medici, Gian Gastone de' (jän gästôˈnā dā mĕˈdĭchē, Ital. māˈdēchē) [key], 1671–1737, grand duke of Tuscany (1723–37); son and successor of Cosimo III de' Medici. Gian Gastone was the last male member of his family, and the question of succession caused agitation from 1715 onward. In 1735 it was settled, in connection with the general territorial exchanges caused by the War of the Polish Succession, that on Gian Gastone's death Tuscany should fall to Francis of Lorraine (later Holy Roman Emperor Francis I), husband of Maria Theresa of Austria, in exchange for Lorraine, which went to Stanislaus I of Poland. When Francis became grand duke, Tuscany had fallen from its former glory to decadence and impoverishment.