The French Invasion of Russia, known in Russia as the Patriotic War of 1812 and in France as the Russian Campaign , began on 24 June 1812 when Napoleon's crossed the Neman River in an attempt to engage and defeat the Russian army. Napoleon hoped to compel Tsar Alexander I of Russia to cease trading with British merchants through proxies in an effort to pressure the United Kingdom to sue for peace. The official political aim of the campaign was to liberate Poland from the threat of Russia. Napoleon named the campaign the Second Polish War to gain favor with the Poles and provide a political pretext for his actions.