Francis I (German: Franz Stefan, French: François Étienne; 8 December 1708 – 18 August 1765) was Holy Roman Emperor and Grand Duke of Tuscany, though his wife effectively executed the real powers of those positions. With his wife, Maria Theresa, he was the founder of the Habsburg-Lorraine dynasty. From 1728 until 1737 he was Duke of Lorraine. In 1737, Lorraine became managed by France under terms resulting from the War of the Polish Succession. Francis and the House of Lorraine received the Grand Duchy of Tuscany in the peace treaty that ended that war. After taking the throne of the Holy Roman Empire, the return of the ancestral duchy of Lorraine went nominally to his brother Prince Charles Alexander of Lorraine (who was however engaged in ruling the Austrian Netherlands), until succession under derivate house alliances resulted in Lorraine's annexation to France in 1766.

Francis was born in Nancy, Lorraine (now in France), the oldest surviving son of Leopold, Duke of Lorraine, and his wife Élisabeth Charlotte d'Orléans. He was connected with the Habsburgs through his grandmother Eleonor, daughter of Emperor Ferdinand III. He was very close to his brother and sister Anne Charlotte.

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