King Louis XVIII of France. By 1812, France dominated most of Europe under the leadership of Napoleon. Soon after, he lost many of his political supporters and abdicated the throne in April 1814. The following year, Louis XVI's brother returned from Brussels to rule as King Louis XVIII. When Napoleon regained control of France, it became known as the Hundred Days. Louis XVIII fled to Belgium during this time and returned to France after the defeat of Napoleon at the Battle of Waterloo. He then established a constitutional monarchy, but after 1820 he was increasingly dominated by the ultra royalists. After Louis XVIII's death in 1824, his younger brother, Charles X, the favorite of the ultra royalists, ascended the throne.