Napoléon François Charles Joseph Bonaparte, Prince Imperial, King of Rome, Prince of Parma (20 March 1811 – 22 July 1832), after 1818 known as Franz, Duke of Reichstadt, was the son of Napoleon I, Emperor of the French, and his second wife, Marie Louise of Austria. By Title III, article 9 of the French Constitution of the time, he was Prince Imperial, but he was also known from birth as the King of Rome which Napoleon I declared was the courtesy title of the heir-apparent. His nickname L'Aiglon ("the Eaglet") was awarded posthumously and was popularized by the play by Edmond Rostand L'Aiglon. When his father abdicated on 4 April 1814, he named his son Emperor, but the coalition partners that had defeated Napoleon refused to acknowledge his son as successor, so he was forced to abdicate unconditionally a week later. Although he never actually ruled France, he was the titular Emperor and he is still generally referred to by historians as Napoleon II.