Franco-Prussian War

In the summer of 1870 Napoleon III's France went to war with Prussia and its German allies, and within six weeks it had lost an army and its emperor. The fighting, which lasted from July 1870 to the end of January 1871, toppled the Second Empire, led to the founding of a French republic, and ended with the German states united as a single empire. France also lost Alsace and much of Lorraine, a grievance that poisoned relations between the two countries for decades.

Prussia's crushing victory over Austria in 1866 and its leadership of the new North German Confederation alarmed France, which had seen itself as the leading power on the continent. The Prussian minister-president, Otto von Bismarck, believed a war with France would bring the independent southern German states of Bavaria, Württemberg, Baden and Hesse-Darmstadt over to Prussia, especially if France appeared to be the aggressor. Historians still debate whether he deliberately provoked the conflict or simply exploited events.

The trigger was the offer of the vacant Spanish throne to Prince Leopold of Hohenzollern-Sigmaringen, from a Catholic branch of the Prussian royal house. France objected, and the candidacy was withdrawn, but the French then demanded a promise from King Wilhelm I at Ems that it would never be renewed. Wilhelm refused, and Bismarck released an edited account of the exchange that made it sound insulting. Crowds in Paris called for war. France mobilised on 15 July and declared war on 19 July 1870, and the southern states joined Prussia at once.

German mobilisation, organised by the General Staff under Helmuth von Moltke and driven by railways, was far faster than the French. The French had the better rifle, the Chassepot, but the Germans had superior steel breech-loading artillery from Krupp. After a brief French move into Saarbrücken, three German armies crossed the frontier and won at Wissembourg, Spicheren and Wörth in early August. Marshal Bazaine's Army of the Rhine was then blocked at Mars-la-Tour and, after the costly Battle of Gravelotte on 18 August, shut up inside the fortress of Metz.

A second army under Marshal MacMahon, accompanied by Napoleon III, marched to relieve Metz but was trapped at Sedan near the Belgian border. On 1 September German guns pounded the encircled French from several sides, and the next day the emperor surrendered with more than 100,000 men. When the news reached Paris, the Second Empire collapsed, and on 4 September a Government of National Defence proclaimed a republic. Bazaine's army at Metz surrendered on 26 October, with some 173,000 people taken.

German forces began besieging Paris on 19 September. Léon Gambetta escaped from the city by balloon and raised new armies in the provinces, but these were defeated one after another. On 18 January 1871, while Paris was still under siege, Wilhelm I was proclaimed German Emperor in the Hall of Mirrors at Versailles. With the city starving, the French government agreed an armistice, and Paris capitulated on 28 January.

German records list about 28,000 battle deaths and some 12,000 deaths from disease. French losses were far heavier: around 77,000 battle deaths, more than 45,000 deaths from sickness, and over 380,000 men taken prisoner.

The Treaty of Frankfurt, signed on 10 May 1871, required France to pay an indemnity of five billion francs and to hand over most of Alsace and part of Lorraine, which became the imperial territory of Alsace-Lorraine. Anger at the defeat and the peace terms helped spark the Paris Commune in the spring of 1871. The war completed the unification of Germany, made the new German Empire the strongest land power in Europe, and fed a lasting French desire for revenge.

Our 1815 map shows the German lands still divided among many states, including the Kingdom of Prussia. The 1878 map shows the new German Empire beside France after the war.