The Single-Day Battle South of Brussels on 18 June 1815 That Ended Napoleon's Hundred Days, Cost Approximately 60,000 Casualties, and Began the Century of British Naval Hegemony

Napoleon had been exiled to Elba after his April 1814 abdication. He escaped on 26 February 1815 with about 1,000 men, landed in southern France on 1 March, and reached Paris on 20 March having gathered approximately 200,000 supporters along the way. King Louis XVIII had fled. Napoleon resumed the French throne for what became the Hundred Days.

The Seventh Coalition (Britain, Prussia, Austria, Russia, and several smaller states) declared Napoleon an outlaw and mobilised approximately 700,000 troops across Europe. Napoleon’s strategic choice was to attack the two nearest coalition armies — Wellington’s Anglo-allied army in Belgium and Blücher’s Prussian army to its east — before the slower Austrian and Russian forces could arrive.

He crossed into Belgium on 15 June 1815.

Three days

The campaign produced three engagements over four days. On 16 June 1815 Napoleon defeated Blücher at Ligny (Prussian casualties approximately 16,000; French approximately 13,000) and simultaneously fought Wellington to a draw at Quatre Bras about 10 km away. The Prussians retreated north toward Wavre, not east as Napoleon had assumed. Wellington fell back to the ridge of Mont-Saint-Jean south of Brussels — Waterloo.

Heavy rain on 17 June 1815 turned the fields to deep mud. Napoleon delayed his attack on 18 June until about 11:30 a.m. to let the ground dry.

18 June 1815

The French attack ran from late morning to early evening. The French infantry assault on Wellington’s centre at La Haye Sainte made limited progress; the cavalry charges of Marshal Ney against Wellington’s infantry squares were repulsed at heavy cost; the Imperial Guard assault late in the afternoon broke against the British line of the Foot Guards.

The Prussians began arriving on Napoleon’s right flank at about 4:30 p.m. They captured the village of Plancenoit, threatening Napoleon’s rear. By approximately 8 p.m. the French army was broken and in full retreat. Wellington and Blücher met at La Belle Alliance farmhouse at about 9 p.m. and confirmed the joint victory.

Casualties were approximately:

— French: 25,000 killed or wounded, 8,000 captured — Anglo-allied: 17,000 killed or wounded — Prussian: 7,000 killed or wounded

Total: approximately 57,000-60,000 casualties in roughly ten hours. The intensity per hour was higher than at most subsequent battles of comparable size.

What it ended

Napoleon reached Paris on 21 June 1815 and abdicated for the second time on 22 June. He attempted to escape to the United States from Rochefort but found the harbour blockaded by the Royal Navy. He surrendered to Captain Frederick Maitland of HMS Bellerophon on 15 July 1815 and was exiled to Saint Helena on 7 August 1815. He died there on 5 May 1821.

The Congress of Vienna that followed (which had been in session before Waterloo) finalised the territorial settlement of post-Napoleonic Europe. The settlement held for 99 years until the First World War.

Wellington became one of the most prominent British political figures of the next four decades, serving as Prime Minister 1828-1830. He died on 14 September 1852, aged 83. Blücher died of natural causes on 12 September 1819, aged 76.

The English-language phrase “to meet one’s Waterloo” — meaning a final and decisive defeat — entered the language by approximately 1830. It has not been replaced.