Louis XVII (born Louis Charles, Duke of Normandy; 27 March 1785 – 8 June 1795) was the younger son of King Louis XVI of France and Queen Marie Antoinette. His older brother, Louis Joseph, Dauphin of France, died in June 1789, a little over a month before the start of the French Revolution. At his brother's death he became the new Dauphin (heir apparent to the throne), a title he held until 1791, when the new constitution accorded the heir apparent the title of Prince Royal.
When his father was executed on 21 January 1793, during the middle period of the French Revolution, he automatically succeeded as King of France, Louis XVII, in the eyes of the royalists. France was by then a republic and since Louis-Charles was imprisoned and died in captivity in June 1795, he never actually ruled. Nevertheless, in 1814 after the Bourbon Restoration, his uncle acceded to the throne and was proclaimed Louis XVIII.
Source : Wikipedia
