Napoleon fought in Austria, Spain, and Germany, where he won great victories (Marengo, Ulm, Austerlitz, Samosierra, Wagram). He defeated Prussia at the battles of Jena and Auerstedt and Russia at Friedland. He suffered defeats at sea at Abu Kire and Trafalgar. When the alliance with Alexander I began to weaken due to growing international tension, Napoleon declared war on the Russian Empire in 1812. The French fought two victorious battles there - at Smolensk and Borodino. Napoleon ventured far to the east, and when it became clear that he would not be able to wait out the harsh winter in Moscow, which had been deliberately burned by the Russians, he ordered a retreat. The Russians did not agree with Napoleon's proposed quick peace; instead, they harassed the Grand Army with constant attacks by the regular Russian army, Cossacks, and partisans. In addition, gigantic frosts decimated the Grand Army, which suffered a severe defeat in Russia.
