Archduke Ferdinand Karl of Austria-Este was a son of Holy Roman Emperor Franz I and Maria Theresa of Austria. He was the founder of the House of Austria-Este and Governor of the Duchy of Milan between 1765 and 1796. He was also designated as the heir to the Duchy of Modena and Reggio, but he never reigned, owing to the Napoleonic Wars.

Francis I was Holy Roman Emperor, Archduke of Austria, Duke of Lorraine and Bar, and Grand Duke of Tuscany. He became the ruler of the Holy Roman Empire of the German Nation, Austria, and Tuscany through his marriage to Maria Theresa, daughter of Emperor Charles VI. Francis was the last non-Habsburg monarch of the Empire. The couple were the founders of the Habsburg-Lorraine dynasty, and their marriage produced sixteen children.