Napoleon III was the first President of France from 1848 to 1852 and the Emperor of the French from 1852 to 1870. A nephew of Napoleon I, he was the last monarch to rule over France. Elected to the presidency of the Second Republic in 1848, he seized power by force in 1851, when he could not constitutionally be reelected; he later proclaimed himself Emperor of the French. He founded the Second Empire, reigning until the defeat of the French Army and his capture by Prussia and its allies at the Battle of Sedan in 1870.