Louis XVIII ruled as king for slightly less than a decade. The government of the Bourbon Restoration was a constitutional monarchy, unlike the "Ancien Régime", which was absolutist. 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, referred to as 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, so upon his death the crown passed to his brother, Charles X. Louis XVIII was the last French monarch to die while still reigning, as Charles X (1824–1830) abdicated and both Louis Philippe I (1830–1848) and Napoleon III (1852–1870) were deposed.