The battle that marked the final defeat of Napoleon in 1815 was the Battle of Waterloo. Fought on June 18, this significant encounter involved Napoleon's French army facing a coalition led by the Duke of Wellington and the Prussian forces under Gebhard Leberecht von Blücher. The defeat signaled the end of Napoleon's rule and the Napoleonic Wars, leading to his exile on the island of Saint Helena. The outcome had lasting implications for Europe, resulting in a new balance of power established at the Congress of Vienna and shaping European politics for the rest of the 19th century.