Causes of 1870–1871 war
The causes of the Franco-Prussian War are deeply rooted in the events surrounding German unification. In the aftermath of the Austro-Prussian War (1866), Prussia had annexed numerous ethnically German territories and formed the North German Confederation with other German territories. Prussia then turned its attention towards the south of Germany, where it sought to expand its influence.
France was strongly opposed to the annexation of the Southern German States (Bavaria, Wurttemberg, Baden and Hesse-Darmstadt) by the North German Confederation, which would have created too powerful a country next to its border. In Prussia, a war against France was deemed necessary to arouse German nationalism in those States in order to allow the unification of most German states (excluding the ethnically German lands of the Austrian Empire) into a great German empire. This aim was epitomized by Prussian Chancellor Otto von Bismarck's quote: "I knew that a Franco-Prussian War must take place before a united Germany was formed." Bismarck also knew that France should be the aggressor in the conflict to bring the Southern German States to side with Prussia, hence giving Germans numerical superiority.
The immediate cause of the war resided in the candidacy of a Prussian prince to the throne of Spain – France feared encirclement by an alliance between Prussia and Spain. The Hohenzollern prince's candidacy was withdrawn under French diplomatic pressure, but Otto von Bismarck goaded the French into declaring war by altering a dispatch sent by William I. Releasing the Ems Dispatch to the public, Bismarck made it sound as if the king had treated the French envoy in a demeaning fashion. Six days later, France declared war on Prussia and the Southern German States immediately sided with Prussia.
French Emperor Napoleon III and Prime Minister Émile Ollivier's eagerness to relieve France from internal political convulsions also contributed to France's declaration of war on Prussia.
European wars and the balance of power: 1865–1866.
In October 1865, Napoleon III, ruler of France, met with Prussian Prime Minister Otto von Bismarck in Biarritz, France. It was there that the two men struck a deal— France would not get involved in any future actions between Prussia and Austria or ally herself with Austria if Prussia somehow won the war and did not allow Italy to claim Venetia. When Austria and Prussia met in May 1866, Bismarck honored the agreement made in Biarritz the previous year and refused to allow Austria to have Venetia. Austria then attempted to guarantee Italy Venetia if they remained neutral, but the two nations were unable to agree on a suitable arrangement as an alliance formed earlier in the year bound Italy to Prussia. Napoleon III then committed a serious blunder by agreeing with Austria in a secret treaty to remain neutral in an Austrian-Prussian conflict in exchange for France acquiring Venetia plus the establishment of a neutral (i.e., French-leaning) state west of the Rhine; this violated the agreement Napoleon had made with Bismarck.
After Prussia emerged victorious over the Austrian army at the Battle of Königgrätz (also known as Sadowa or Sadová) in the Austro-Prussian War of 1866, negotiations were being held between Austria and Prussia in July and August of that year. It was during that period that Napoleon III first discovered that a bladder stone was causing him great pains, created from gonorrheal infection. His condition was so bad during those negotiations that he was forced to retire to Vichy to recuperate, removing himself from Paris. Although the emperor favored neutrality as to not upset events, certain members of his circle thought it was an unwise move, considering the opportunity to prevent Prussia from becoming too strong. One of these men, foreign minister Édouard Drouyn de Lhuys, convinced the emperor to plant 80,000 men on the eastern border to convince Wilhelm I to maintain the balance of power in Europe. Despite this important victory, de Lhuys was subverted by several other ministers, and Napoleon III changed his mind, reverting to a position of neutrality. This change of heart would end up causing de Lhuys to ultimately lose his position. Napoleon III's wife Empress Eugénie, who took an active part throughout his rule, referred to this time much later as "the critical date, the Empire's fatal date; it was during these months of July and August that our fate was sealed! Of all that period, there is not a single fact, not a single detail that has not remained in my mind."
Franz Joseph of Austria accepted Bismarck's terms under the Peace of Prague. Using this to his advantage, Bismarck declared the German Confederation of 1815 null and void, and created a new network of states under Prussian control. Frankfurt-am-Main, Hannover, Hesse-Kassel (or Hesse-Cassel), Holstein, Nassau, and Schleswig were annexed outright while Hesse-Darmstadt, Mecklenburg, Saxony, the Thuringian duchies, as well as the cities of Bremen, Hamburg, and Lübeck were combined into a new North German Confederation that governed nominally and was actually controlled by Prussia herself.
Bismarck was approached soon after the end of the war by Napoleon III's ambassador to Prussia, Vincent Benedetti. Benedetti brought with him a secret proposal by Napoleon III that France would approve of Bismarck's acquisition of the northern German states if Prussia remained neutral while France annexed Belgium and Luxembourg. France had earlier guaranteed the independence of Belgium in the Treaty of London in 1839 as an "independent and perpetually neutral state", making the proposal a tacit agreement to break their promise. Bismarck was very surprised since he had already gained a powerful position in Europe by the armistice, and called Napoleon III's request among others later "like 'an innkeeper's bill' or a waiter asking for 'a tip'." He asked Benedetti to provide the proposal in writing, and the ambassador obliged his request. This document was to be important to Bismarck later on, to great effect.
The true views of Napoleon III on the subject of the balance of power in Europe can be found in a state circular handed to every diplomatic representative for France. In this paper dated September 1, 1866, the emperor saw the future of Europe after the Peace of Prague in this manner:
"Policy should rise superior to the narrow and mean prejudices of a former age. The Emperor does not believe that the greatness of a country depends upon the weakness of the nations which surround it, and he sees a true equilibrium only in the satisfied aspirations of the nations of Europe. In this, he is faithful to old convictions and to the traditions of his race. Napoleon I foresaw the changes which are now taking place on the continent of Europe. He had sown the seeds of new nationalities: in the Peninsula, when he created the Kingdom of Italy; and in Germany, when he abolished two hundred and fifty three separate states."
Domestic agenda in France and Prussia.
French prestige and 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. 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 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 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.
Bismarck had an entirely different view after the war in 1866: he was interested only in strengthening Prussia through the eyes of a staunch realist. Uniting Germany appeared immaterial to him unless it improved Prussia's position. Bismarck had mentioned before the war the possibility of ceding territory along the Rhine to France, and Napoleon III, urged by his representatives in France, used these casual references by Bismarck to press for more of the territory that Prussia had received from Austria. These discussions, leaked by Bismarck to the German states in the south, turned former enemies into allies almost overnight, receiving not only written guarantees but armies that would be under the control of Prussia.
Alliances and diplomacy.
German states.
Diplomatically and militarily, Napoleon III looked for support from Austria, Denmark, Bavaria, Baden, and Württemberg, as all had recently lost wars against Prussia. However, Napoleon III failed to secure revanchist alliances from these states. Denmark had twice fought Prussia during the First and Second Wars of Schleswig (a victory in the 1848–50, and a defeat in 1864 against a confederation of North German states and Austria under the leadership of Prussia), and was unwilling to confront Prussia again. As part of the settlement of the Austro-Prussian War in 1866, secret treaties of mutual defense were signed between Prussia and Bavaria, Baden, and Württemberg. What made them especially significant was that not only were they secret, giving Napoleon III a false sense of security, but Bismarck had used Napoleon III's earlier demand of territory along the Rhine to drive the southern German states into his arms. By these treaties, Prussia would defend all of the southern German states with its military power as long as their states joined the Northern Confederation in defense of Prussia. It was a bargain that would gravely threaten the French "empereur" and his designs on restoring French pride.
Austria and Italy.
The Austrian Chancellor Friedrich Ferdinand von Beust was "impatient to take his revenge on Bismarck for Sadowa." As a preliminary step, the "Ausgleich" with Hungary was "rapidly concluded." Beust "persuaded Francis Joseph to accept Magyar demands which he had till then rejected.". However, Austria would not support France unless Italy was part of the alliance. Victor Emmanuel II and the Italian government wanted to support France, but Italian public opinion was bitterly opposed so long as Napoleon III kept a French garrison in Rome protecting Pope Pius IX, thereby denying Italy the possession of its capital (Rome had been declared capital of Italy in March 1861, when the first Italian Parliament had met in Turin). Napoleon III made various proposals for resolving the Roman Question, but Pius IX rejected them all. Despite his previous support for Italian unification, Napoleon did not wish to press the issue for fear of angering Catholics in France. Raffaele De Cesare, an Italian journalist, political scientist, and author, noted that:
The alliance, proposed two years before 1870, between France, Italy, and Austria, was never concluded because Napoleon III [...] would never consent to the occupation of Rome by Italy. [...] He wished Austria to avenge Sadowa, either by taking part in a military action, or by preventing South Germany from making common cause with Prussia. [...] If he could insure, through Austrian aid, the neutrality of the South German States in a war against Prussia, he considered himself sure of defeating the Prussian army, and thus would remain arbiter of the European situation. But when the war suddenly broke out, before anything was concluded, the first unexpected French defeats overthrew all previsions, and raised difficulties for Austria and Italy which prevented them from making