Battle of Waterloo

Napoleon had escaped Elba in March 1815 and retaken France without firing a shot, forcing King Louis XVIII to flee. The European powers—Britain, Prussia, Austria, and Russia—immediately mobilized to stop him. By mid-June, British commander the Duke of Wellington and Prussian commander Gebhard Blücher had positioned their armies in southern Belgium, waiting.

On June 18, Napoleon attacked Wellington's 67,000-strong force near the village of Waterloo. The French commander, convinced Blücher's Prussians were still a day away, pressed for a quick victory. His cavalry charged repeatedly against British infantry squares—disciplined formations that held firm. The fighting lasted all day, with neither side breaking through. Around 4 p.m., Prussian forces under General Johann von Zieten began arriving on Napoleon's right flank, exactly as Wellington had hoped.

Napoleon threw his elite Imperial Guard into a final assault around 7 p.m. These veteran troops, considered unbeatable, were repulsed by British infantry and cavalry under Sir John Colborne. As darkness fell and Prussian reinforcements continued pouring in, French lines collapsed. What followed was a rout. Soldiers threw down weapons and fled; wagons overturned; thousands were captured or killed. By 8 p.m., Wellington and Blücher met on the battlefield and agreed the day was won.

The casualty count was staggering. France lost roughly 25,000 men killed or wounded, plus 8,000 captured. Allied losses—about 22,000 total—were nearly as severe, but replacements were available. More importantly, the Prussians and Dutch kept pursuing Napoleon's army for days afterward, preventing any chance of regrouping.

Napoleon abdicated four days later and was exiled to St. Helena, a remote island in the Atlantic. The Concert of Europe settled into a new order at the Congress of Vienna, where the major powers carved up the map to prevent any single nation from dominating again. Waterloo didn't just end one man's ambitions—it ended an era of revolutionary warfare and ushered in a century of relative (if unstable) great-power peace.