The period in Britain from 1811 to 1820 when the Prince of Wales, later George IV, acted as regent for his father, George III, who had become insane. Among the major events of the Regency were the War of 1812 involving Britain and the USA, the successful conclusion of the Napoleonic Wars, and the Congress of Vienna (1814–15). In Britain the post-war period was marked by a slump in the economy, which caused much social unrest. The Tory government used severe measures to quell popular discontent, which culminated in the Peterloo Massacre of 1819.