1866: AUSTRO-PRUSSIAN WAR

The main opponent to Bismarck's plan for unification was defeated in just seven weeks

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Bismarck had raised German national consciousness with the Second Schleswig War, now it was time to put Prussia at the heart of it. But since the fall of the Holy Roman Empire in 1805, it was Austria and her Habsburg kings who had been leaders of the German Confederation and Bismarck needed them out of the way. His Austro-Prussian War was a carefully planned stage in the unification of Germany.

Bismarck’s pretext for war was the Schleswig-Holstein debate that had been quarrelled over between the two powers for over a year. In January 1866, Prussia protested Austria’s idea of joint elections across both duchies and argued it defied previous agreements. A diplomatic fallout ensued and by March both countries had mobilised their armies on the joint border.

Bismarck now went about ensuring that none of the Great Powers, especially Russia, would intervene should war break out and he found none were interested in protecting Austria. Then, in April, he forged an alliance with the Italians, who wanted Austria to hand over the region of Venetia so they could complete their own unification. This would mean Austria fighting on two fronts and diverting attention and resources away from Prussia. With these assurances in place, Bismarck forced Austria into war by invading Holstein on 9 June, with Austria declaring war on Prussia on 14 June.