Order of the Iron Crown (Austria)
The Holy Roman Empire, ruled by the Habsburg dynasty, gave way to the Empire of Austria between 1804 and 1806. The last Holy Roman Emperor, Franz II, was proclaimed Emperor Franz I of Austria. His daughter, the Archduchess Maria Louise, was Napoleon’s second wife and Empress Consort, and the mother of Napoleon’s only legitimate son and heir, Napoleon, Duke of Reichstadt. With the collapse of Napoleon’s empire, Imperial Austria regained its traditional control of Lombardy as the Kingdom of Lombardy–Venetia.
Constantine VI
Constantine VI was the final ruler to be universally recognized as Roman Emperor, being recognized as such by both the Empire which he ruled in the east, the papacy and the Western European powers over which the pope held suzerainty. With his mother becoming Empress regnant upon his deposition, the papacy crowned Charlemagne as a new Emperor in Western Europe, asserting that a woman could not be Empress in her own right. This laid the foundations of a new polity, independent of the East, that would evolve into the "Holy Roman Empire".