June 1866-August 1866
The Seven Weeks' War (also called the Austro-Prussian War) pitted Prussia and Italy against Austria and most of the smaller German states. The war grew out of the increasing embitterment of Austro-Prussian relations since 1849, when Prussia tried to exploit revolutionary upheaval in central Europe to wrest control of the German Confederation from Austria. Despite the recent expansion and modernization of the Prussian army, most observers anticipated an Austrian victory—which made the speed and finality with which Prussia crushed its larger opponent all the more impressive. In the aftermath Austria gave up its rights in Germany and ceded Venetia to France, which presented it to Italy. Northern Germany was reorganized as a confederation under Prussian auspices, to which the southern kingdoms were bound by treaty.
Prussia's victory stemmed from a combination of political and military advantages.
Otto von Bismarck's securing of French and Russian neutrality meant that Austria would fight, for practical purposes, alone. His opportunistic alliance with Italy was likewise useful in drawing Austrian forces away from Prussia. Years of planning by
Helmuth von Moltke's General Staff in the use of railroads and telegraphy to move and control large forces also paid off, by allowing three independent Prussian armies to advance concentrically against a concentrated and static foe.
The decisive battle of the war occurred at
Königgrätz, where the Austrians narrowly escaped the envelopment Moltke had planned for them. Given the will, Austria might have fought on for months. To have done so, however, would have risked French intervention and even civil war, without doing anything to redeem Austria's preeminence in Germany, now lost forever.