The Franco-Prussian War (July 19, 1870 – May 10, 1871) was declared by France on Prussia, which was backed by the North German Confederation and the south German states of Baden, Württemberg and Bavaria. The conflict marked the culmination of tension between the two powers following Prussia's rise to dominance in Germany, which before 1866 was still a loose federation of quasi-independent territories.
The war began over the possible ascension of a candidate from the Catholic branch of the Hohenzollern royal family to the vacant Spanish throne as Isabella II had abdicated in 1868. This was strongly opposed by France who issued an ultimatum to King Wilhelm I of Prussia to have the candidacy withdrawn, which was done. Aiming to humiliate Prussia, Emperor Napoleon III of France then required Wilhelm to apologize and renounce any possible further Hohenzollern candidature to the Spanish throne. King Wilhelm, surprised at his holiday resort by the French ambassador, declined as he was not informed yet. Prussia's Chancellor, Otto von Bismarck, edited the King's account of his meeting with the French ambassador to make the encounter more heated than it really was. Known as the Ems Dispatch, it was released to the press. It was designed to give the French the impression that King Wilhelm I had insulted the French Count Benedetti, and to give the German people the impression that the Count had insulted the King. It succeeded on both accounts.
The French people and their parliament reacted with outrage; Napoleon III mobilized and declared war on Prussia only, but effectively also on the states of southern Germany. The German armies quickly mobilized and within a few weeks controlled large amounts of land in Eastern France. Their success was due in part to rapid mobilization by train, to Prussian General Staff leadership and to modern Krupp artillery made of steel. Napoleon III was captured with his whole army at the Battle of Sedan, yet this did not end the war, as a republic was declared in Paris on September 4, 1870, marking the creation of the Third Republic of France under the Government of National Defense and later the "Versaillais government" of Adolphe Thiers. The immediate result was an extension to the war as the Republic proclaimed a continuation of the fight.
Over a five-month campaign, the German armies defeated the newly recruited French armies in a series of battles fought across northern France. Following a prolonged siege, the French capital Paris fell on January 28, 1871. Ten days earlier, the German states had proclaimed their union under the Prussian King, uniting Germany as a nation-state, the German Empire. The final peace Treaty of Frankfurt was signed May 10, 1871, during the time of the bloody Paris Commune of 1871.
In France and Germany the war is known as the Franco-German War (French: Guerre franco-allemande de 1870 German: Deutsch-Französischer Krieg), which perhaps more accurately describes the combatants rather than simply France and Prussia alone.
Causes of the war
Tensions had long been running high between Prussia and France following the Prussian victory in the Austro-Prussian War of 1866 and its subsequent annexation of almost all Northern Germany. The humbling of Austria and Prussia's new territorial gains had shattered the European balance of power that had existed since the end of the Napoleonic Wars.
Prussian Prime Minister Otto Von Bismarck, after proving Prussia to be the most powerful of German States in the Austro-Prussian War, wanted to once again unite the German States under the Prussian banner. This would allow a Prussian Emperor to rule all of the German States in a united German Empire. It would also lead to a more prosperous age in which the might of the German Empire would be unparalleled in Europe.
Following the end of the Austro-Prussian War, Prussian prime minister Otto von Bismarck and the French emperor Napoleon III had attempted to reach a private agreement regarding the balance of power in Europe. Napoleon III wished to realise French aspirations for "natural borders," a long term goal of French foreign policy since the Middle Ages — to annex all land west of the Rhine river and the Alps including the German state of Palatinate-on-Rhine, Belgium, the southern Netherlands, Luxembourg, Savoy, and parts of Hesse and Rhenish Prussia. A solid defensible border was also insurance against the possibility of a united Germany unfriendly to France. However in 1840 the French politician Adolphe Thiers had sparked a Franco-German diplomatic crisis (the Rhine crisis, 1840) over a mention of "natural borders" on the west bank of the Rhine, reminding many Germans of Napoleonic efforts to establish a border on the Rhine.
Savoy had been obtained from Italy following French support for Italian independence from Austria. Now Napoleon III sought Prussian neutrality when attempting to acquire Luxembourg and Wallonia (the French-speaking part of Belgium), while expecting Prussian neutrality as "compensation" for French neutrality during the Austro-Prussian War and for Prussian territorial gains. Bismarck was non-committal at best, but to the French government, Bismarck appeared to agree to or at least agreed not to obstruct any French moves against the Low Countries.
Luxembourg crisis
Thus in 1867, France began by negotiating the purchase of Luxembourg from the Dutch government, as Luxembourg was then in personal union with the Netherlands. Assuming that Bismarck would honour his part of the agreement, the French government was shocked to learn that instead Bismarck, Prussia and the North German Confederation were threatening war should the sale be completed. Luxembourg lay astride one of the principal invasion routes an army would use to invade either France or Germany. The city of Luxembourg's formidable fortifications, constructed by the famous military engineer Marshal Vauban, were considered "the Gibraltar of the North", and neither side could tolerate the other controlling such a strategic location. To mediate the dispute, the United Kingdom hosted the London Conference (1867) attended by all European great powers. It confirmed Luxembourg's independence from the Netherlands and guaranteed its independence from all other powers. War appeared to have been averted, at the cost of thwarting French desires.
French prestige and domestic politics
France's position in Europe was now in danger of being overshadowed by the emergence of a powerful Prussia, and France looked increasingly flat-footed following Bismarck's successes. In addition, French ruler Napoleon III was on increasingly shaky ground in domestic politics. Having successfully overthrown the Second Republic and established the Bonapartist Second Empire, Napoleon III was confronted with ever more virulent demands for democratic reform from leading republicans such as Jules Favre, along with constant rumours of impending revolution. In addition, French aspirations in Mexico had suffered a final defeat with the execution of the Austrian-born, French puppet Emperor Maximilian I of Mexico in 1867.
The French imperial government now looked to a diplomatic success to stifle demands for a return to either a republic or a Bourbon monarchy — the Empress Eugénie, wife of Napoleon III, was quoted as saying, "If there is no war, my son will never be emperor." A war with Prussia and resulting territorial gains in the Rhineland and later Luxembourg and Belgium seemed the best hope to unite the French nation behind the Bonapartist dynasty. With the resulting prestige from a successful war, Napoleon III could then safely suppress any lingering republican or revolutionary sentiment behind reactionary nationalism and return France to the center of European politics.
Bismarck and German nationalism
Prussia in turn was also beset with problems. While revolutionary fervour was far more muted than in France, Prussia had in 1866 acquired millions of new, suspect citizens as a result of the Austro-Prussian War which was also a civil war among German states. The remaining German kingdoms and principalities maintained a steadfastly parochial attitude towards Prussia and German unification. The German princes insisted upon their independence and balked at any attempt to create a federal state that would be dominated by Berlin. Their suspicions were heightened by Prussia's quick victory and her subsequent annexations. Before the war, only some Germans, inspired by the recent unification of Italy, accepted and supported what the princes began to realise: That Germany must unite in order to preserve the fruit of an eventual victory.
The Prussian premier Otto von Bismarck had an entirely different view. He was interested only in strengthening Prussia and the power of her king. Uniting Germany appeared immaterial to him unless it improved Prussia's position. Bismarck considered the conflict with France inevitable, knowing that France would not quietly tolerate a powerful state to its east. He also viewed the war as a means to end the influence which France had long since exercised over Germany. The defeated South German states had to sign mutual defense treaties with the North German Confederation, but only a clear aggression from outside could make sure they would ally with Prussia, rather than against her once more.
Crisis and the outbreak of war
Napoleon III and Bismarck independently sought a suitable crisis to forment, and in 1870 one arose. The Spanish throne had been vacant since the revolution of September 1868. The Spanish offered the throne to the German prince Leopold of Hohenzollern-Sigmaringen, a Catholic as well as a distant cousin of King Wilhelm of Prussia.
Fearing that a Hohenzollern king in Prussia and another one in Spain would put France into a two-front situation, Napoleon III was determined this time to stand up to the expansion of Prussian influence. He successfully forced King Wilhelm to urge the prince's withdrawal from his Spanish candidacy. Disappointed that the Prussians had backed down so easily, the French government tried to prolong the crisis. In a newspaper interview, Napoleon III announced that a renewal of the Hohenzollern candidature would result in France going to war, and the secretary of foreign affairs, Duc de Gramont, did the same in a speech in front of the Chambre législative. The French ambassador in Prussia Vincent Benedetti was then ordered to require Wilhelm I to guarantee that no Hohenzollern would ever again be a candidate for the Spanish throne. When the French ambassador bypassed diplomatic channels and directly confronted the king at his holiday resort, King Wilhelm was "very polite but cooly categorical". His message to Berlin (the Ems Dispatch) reporting this event with the French ambassador reached the desk of Bismarck. Bismarck edited the telegram in such a way as to arouse French indignation, and then released it for publication.
France officially declared war on July 19, 1870.