Since France had been defeated on these two fronts, states it previously conquered and controlled struck back. The Sixth Coalition was formed, and the German states of the Confederation of the Rhine switched sides, finally opposing Napoleon. Napoleon was defeated in the Battle of the Nations outside Leipzig in October 1813. The Allies invaded France and Napoleon abdicated on 6 April 1814. The conservative Congress of Vienna reversed the political changes that had occurred during the wars. Napoleon's attempted restoration, a period known as the Hundred Days, ended with his final defeat at the Battle of Waterloo in 1815. The monarchy was restored with Louis XVIII as king, followed by his brother. France was soon integrated into the reactionary international situation. However much of the Napoleonic liberalization of Western Europe, including Italy, and Germany, and adjacent areas became permanent.