Louis XVIII (Louis Stanislas Xavier; 17 November 1755 – 16 September 1824), known as the Desired (French: le Désiré), was King of France from 1814 to 1824, except for a brief interruption during the Hundred Days in 1815. Before his reign, he spent 23 years in exile from France beginning in 1791, during the French Revolution and the First French Empire.
Until his accession to the throne of France, he held the title of Count of Provence as brother of King Louis XVI, the last king of the Ancien Régime. On 21 September 1792, the National Convention abolished the monarchy and deposed Louis XVI, who was later executed by guillotine. When his young nephew Louis XVII died in prison in June 1795, the Count of Provence claimed the throne as Louis XVIII.
Following the French Revolution and during the Napoleonic era, Louis XVIII lived in exile in Prussia, Great Britain, and Russia. When the Sixth Coalition first defeated Napoleon in 1814, Louis XVIII was placed in what he, and the French royalists, considered his rightful position. However, Napoleon escaped from his exile in Elba and restored his French Empire. Louis XVIII fled, and a Seventh Coalition declared war on the French Empire, defeated Napoleon again, and again restored Louis XVIII to the French throne.
Louis XVIII ruled as king for slightly less than a decade. His Bourbon Restoration government was a constitutional monarchy, unlike the absolutist Ancien Régime in France before the Revolution. As a constitutional monarch, Louis XVIII's royal prerogative was reduced substantially by the Charter of 1814, France's new constitution. His return in 1815 led to a second wave of White Terror headed by the Ultra-royalist faction. The following year, Louis dissolved the unpopular parliament (the Chambre introuvable), giving rise to the liberal Doctrinaires. His reign was further marked by the formation of the Quintuple Alliance and a military intervention in Spain. Louis had no children, and upon his death the crown passed to his brother, Charles X. Louis XVIII was the last king or emperor of France to die a reigning monarch: his successor, Charles X (r. 1824–1830) abdicated; and both Louis Philippe I (r. 1830–1848) and Napoleon III (r. 1852–1870) were deposed.
Source : Wikipedia