Causes of the Franco-Prussian War.

The Franco-Prussian War of 1870 broke out due to a combination of factors stemming from political ambitions, territorial disputes, and national pride on both sides. One key reason for the outbreak of the war was the relentless efforts of Otto von Bismarck, the Chancellor of Prussia, to unify Germany under Prussian leadership. The earlier wars of 1864 against Denmark and 1866 against Austria had already increased Prussia's power and influence in Europe, leading to the creation of the North German Confederation. Bismarck saw a victorious war against France as the final step in uniting the German states into a single, dominant European power.

Another important factor was the diplomatic dispute over the Spanish succession crisis. The Hohenzollern candidacy for the Spanish throne was withdrawn in July 1870, but the French government insisted that it should never be renewed. This demand was seen as an insult to the honor of the Prussian royal family, and Bismarck manipulated the Ems telegram to provoke the French into declaring war. This desire for revenge and the restoration of Prussian honor further escalated tensions between the two nations.

France, on the other hand, felt threatened by Prussia's growing power in Europe following the victories of 1864 and 1866. The French government wanted to assert its authority and regain its international standing, particularly after the failure of its Mexican expedition. The prospect of a successful war against Prussia was seen as a way to restore French prestige and unity, especially under Napoleon III's Bonapartist regime, which was facing domestic challenges and growing demands for democratic reforms.

Furthermore, recent military reforms in France had instilled confidence in the political and military leadership that they would emerge victorious in any conflict with Prussia. This overconfidence in their military capabilities and the belief in the strategic advantage held by the French army also played a role in the decision to go to war.

Overall, the Franco-Prussian War of 1870 broke out due to a combination of long-term political ambitions, territorial disputes, national pride, and miscalculations on both sides, ultimately leading to a significant shift in the balance of power in Europe with the eventual unification of Germany under Prussian leadership.