Napoleon crowned himself Emperor in 1804. Soon after, he faced the Third Coalition of European powers. His Grande Armée, using the new corps system, swiftly defeated Austria at Ulm and occupied Vienna. The decisive Battle of Austerlitz followed on December 2, 1805.Napoleon's strategy lured Allies into attacking his right while he struck their center on the Pratzen Heights. The French victory shattered the Coalition, forcing Austria to accept harsh terms. However, Britain remained undefeated at sea after Nelson's victory at Trafalgar.The battle showcased Napoleon's tactical brilliance and the effectiveness of his army's organization. It solidified French dominance on land, while Britain ruled the seas. This stalemate between the "whale and the elephant" set the stage for years of continued conflict in Europe.The war's impact was summed up by British PM Pitt: "Roll up that map of Europe, it will not be wanted these ten years.