Title given by the Bonapartists to the son of Napoleon I and Marie Louise; until 1814 he was known as the king of Rome and after 1818 as the duke of Reichstadt. After his father's abdication in 1814 he was taken to the Austrian court, where he spent the rest of his life.
The arms show a Bible open at the Gospel of St John, a Trinitarian symbol. The white cross symbolizes faith. The arms appear on national and state flags. Effective date: 14 September 1863.