Following on from Napoleon's defeated by a coalition of powers this son, a young man of some promise by all accounts, had been raised as an Austrian princeling under the supervision of Metternich but had died of tuberculosis in his early twenties.
As his life ebbed away this young Duke left the great ceremonial sword of honour he had inherited from his father not to any of his surviving Bonaparte uncles but to his cousin Louis Napoleon).
By 1852 Louis Napoleon contrived to overthrew the Republic in the name of order, and styled himself, with the consent of the French electorate, as the Emperor Napoleon III of France.
(Napoleon II being a complimentary titled posthumously imputed to Bonaparte's son from a 'marriage of state' that Napoleon I at the height of his political power had entered into with a daughter of the Austrian Emperor.
Artist - Jacques-Louis David - "The consecration of Napoleon
Louis Napoleon, (who later became the Emperor Napoleon III), attains to power in France offering social stability at home but ultimately follows policies productive of dramatic change in the wider European structure of states and their sovereignty.