Original: Napoléon François Joseph Charles ( Bonaparte ) , Duke of Reichstadt ( 20 March 181122 July 1832 ) , since 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 .
Simplified: After 1815 , the young prince , known as '' Franz '' ( after his maternal grandfather , Emperor Francis of Austria ) , lived in Austria .