
Husband of Maria Theresa, founded the Habsburg-Lorraine line.
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Francis I, then Duke of Lorraine, married Maria Theresa of Austria, uniting the House of Lorraine with the Habsburgs. This marriage founded the Habsburg-Lorraine dynasty and made Francis co-ruler of the Habsburg lands after Maria Theresa's accession.
As part of the agreement for his marriage, Francis I ceded the Duchy of Lorraine to France, receiving the Grand Duchy of Tuscany in compensation. This territorial exchange strengthened French influence in the region and ended Lorraine's independence.
After the death of Charles VII, Francis I was elected Holy Roman Emperor with the support of his wife Maria Theresa. His election restored the imperial title to the Habsburgs, though real power remained with Maria Theresa as ruler of the hereditary lands.
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