Battle of Sedan (1870)

The Battle of Sedan, on 1–2 September 1870, was the decisive encounter of the Franco-Prussian War. German armies under Helmuth von Moltke trapped a French army at the old fortress town of Sedan, near the Belgian border, and forced it to surrender together with Emperor Napoleon III. Within days the Second French Empire had collapsed in Paris, although the war went on for several more months under a new republican government.

By mid-August 1870 the war was going badly for France. After the battle of Gravelotte on 18 August, Marshal Bazaine's Army of the Rhine, some 150,000 men, fell back into the fortress of Metz, where Prussian forces surrounded it. A new French force, the Army of Châlons, was formed under Marshal Patrice de MacMahon, with Napoleon III travelling with it, to march to Bazaine's rescue. Trying to avoid the enemy, it swung north-east towards the Belgian frontier before turning south, a long and exhausting route that left both its flanks exposed.

Moltke saw the opportunity. Leaving two armies to besiege Metz, he sent the Prussian Third and Fourth Armies north. They caught the French at Beaumont on 30 August, inflicting a sharp defeat, and MacMahon gave up the attempt to reach Metz. He withdrew instead to Sedan, an outdated fortress dating from the seventeenth century, to rest and resupply his men, underestimating how strong the Germans were.

The French, about 120,000 to 130,000 strong, faced roughly 200,000 Germans, including Prussian, Saxon and Bavarian troops, with King Wilhelm I of Prussia and his chancellor, Otto von Bismarck, at headquarters. Early on 1 September Bavarian troops crossed the Meuse and attacked the village of Bazeilles, where French marines and local people fought from house to house. MacMahon was wounded early in the day. Command passed first to General Ducrot, who ordered a retreat, and then to General de Wimpffen, who held a government commission to succeed MacMahon and cancelled the retreat in favour of a counter-attack.

Meanwhile German corps swept round to the west and north, and by mid-morning the French were all but encircled. German artillery on the surrounding heights pounded the trapped army. General Margueritte led French cavalry in repeated charges near Floing to open an escape route; he was mortally wounded in the first, and the others were shot down. By mid-afternoon French units were breaking and seeking shelter in the Bois de la Garenne and in the town itself.

Napoleon III ordered a white flag raised over Sedan and sent a letter of surrender to King Wilhelm. Wimpffen tried to obtain honourable terms, but Moltke refused, pointing to the French army's hopeless position and lack of food and ammunition. On 2 September Wimpffen signed the capitulation of the army and fortress. About 104,000 French soldiers went into captivity with 558 guns; the French had also lost about 3,200 killed and 14,800 wounded. German losses were about 9,900, including some 1,300 dead. The emperor was sent into comfortable captivity at Wilhelmshöhe, near Kassel.

After news of the emperor's capture reached Paris, protesters stormed the imperial palace on 4 September and the Second Empire collapsed without bloodshed. A Government of National Defence took over and fought on, and German armies laid siege to Paris from 19 September. The war continued for around five more months, but with one French army captured and the other shut up in Metz, its outcome was no longer in doubt.

In Germany the victory became closely linked with the unification of Germany. Many Germans celebrated 2 September as Sedantag, Sedan Day, until 1919. The battle also features prominently in La Débâcle, Émile Zola's novel of the French collapse.

Our 1815 map shows the Kingdom of Prussia and France before the war, and the 1878 map shows the new German Empire that emerged from it.