The Austro-Prussian War of 1866, also known as the Seven Weeks' War, was the culmination of a century's tension between the two major German powers. Both Prussia and Austria had vested interests in a status quo that acknowledged Austria's primacy of honor in the German lands while accepting Prussia's status in a "special relationship" acknowledging its de facto influence over its smaller immediate neighbors. Neither state, however, fully trusted the other's long-term goodwill—an underlying tension exacerbated after the revolutions of 1848 on one hand by Prussia's growing economic power and on the other by Austria's declining influence in a Europe increasingly shaped by liberalism and nationalism.
It was in that context in August 1864 that Otto von Bismarck, the Prussian minister-president (prime minister), made an offer it seemed Vienna could not refuse. Prussia and Austria had cooperated to prevent Danish absorption of the "German" duchies of Schleswig and Holstein earlier in the year. Now Bismarck proposed their annexation to Prussia in return for a guarantee of Prussian military support against France in Germany and Italy. Was this meant sincerely, or as a ploy to begin levering Austria out of Germany altogether? Vienna was no more scrupulous and no less ambitious than Berlin. Had it become time to draw a line against the whole pack of Junker militarists? Or was it possible to do business even with a profound cynic like Bismarck?
For almost two years the diplomats jockeyed for position in a pas de deux that saw Bismarck increasingly taking the lead. His goal was to force Austria out of Germany and replace the loose German Confederation by a more structured federal system, centered on Berlin and dominated by Prussia. In addition to challenging directly Austria's position in Schleswig-Holstein, he secured French neutrality through discussions of compensation, and Italian cooperation, using as a lure the Austrian-controlled province of Venetia. In February 1866 Austria responded by beginning a mobilization that was intended to deter further Prussian pressure.
While war was not Bismarck's preferred solution, he was ready to accept it as an ultimate alternative. Prussia's King William I was unwilling to embark on what he regarded as a civil war without indisputable evidence of its necessity. That evidence was provided by Helmuth von Moltke, the chief of the general staff, who as the weeks passed made an increasingly compelling case that Prussia could counter Austria's initiative only by prompt, total mobilization based on the state's comprehensive railway network. Nevertheless it was not until May, and then only in a series of limited orders, that William authorized the mobilization and concentration of Prussia's army. Not until mid-June, a week after Austria had called for the German Confederation's mobilization against Prussia, did the king approve an offensive into Bohemia, where the main Austrian army stood waiting.
That inaction was the taproot of Austrian defeat. The army had no prepared plans for war with Prussia. Ludwig von Benedek, commanding the North Army, was unwilling to move in any direction as the Prussians mobilized, concentrated, and finally penetrated Bohemia. Moltke had made a strategic virtue of the technical necessity for initially deploying his forces in an arc determined by the major railway junctions. He proposed to march three armies into Bohemia on separate axes, enmeshing his opponent in a retiarius's net and combining only for battle. Insofar as Benedek possessed a strategy, it was that of a secutor: to turn on and eviscerate Moltke's forces in detail as they came within range.
Benedek's options were further reduced when on 24 June the Austrian South Army won a hard-fought victory over the Italians at Custoza—but paid a price that prohibited the immediate dispatch of reinforcements north of the Alps. The Austrians were nevertheless confident in their ability to defeat the Prussians in pitched battle through the use of shock tactics: massed columns of infantry delivering bayonet charges supported by the fire of a rifled artillery significantly superior to its Prussian counterpart. Instead, once the Prussians came through the Bohemian mountains, the Austrians confronted flexible, small-unit fire tactics based on the needle gun, a breech-loading single-shot rifle that despite its technical shortcomings dominated the battlefields of 1866. In a series of preliminary encounters Austrian losses were so high that, as his battered units reeled back, Benedek abandoned thoughts of an operational offensive. Withdrawing to the Elbe River near the old fortress of Königgrätz, he proposed instead to make the Prussians come to him.
With the Elbe behind him, his position was not optimal. In offering compact high ground it nevertheless resembled the developed Union line at Gettysburg, and the Prussians played an even more obliging role on 3 July 1866 than Robert E. Lee's Confederates had done three years earlier. Their First Army pinned itself down in an abortive frontal attack against entrenchments supported by artillery. The Elbe Army, seeking to envelop the Austrian left flank, made slow and uncertain progress. But Benedek had no grip on the battle, and his subordinates in turn became enmeshed in a futile effort to turn the Prussian left. The North Army was off balance and facing the wrong direction when the Prussian Second Army came in from the northwest, striking the Austrians like a thunderbolt. Only a series of suicidally sacrificial counterattacks enabled Benedek's battered remnants to withdraw across the Elbe.
The "crowning mercy" of Königgrätz deterred any French thoughts of intervention. It convinced the Austrian government to request an armistice on 22 July. William and his generals wanted a victors' peace. Bismarck brokered a compromise that replaced the German Confederation with a North German Confederation firmly under Prussian auspices, but avoided inflicting on Austria the kinds of humiliation that generate long-running antagonism. The Austro-Prussian War was the last of Europe's cabinet wars: a limited conflict for limited objectives. Yet at the same time it established a modern paradigm of deciding wars by single, decisive victories that continues to shape the policy goals of states in the twenty-first century.
Bucholz, Arden. Moltke and the German Wars, 1864–1871. Basingstoke, U.K., 2001.
Craig, Gordon A. The Battle of Königgrätz: Prussia's Victory over Austria, 1866. Philadelphia, 1964. Reprint, Philadelphia, 2003. Still the best introduction.
Showalter, Dennis. The Wars of German Unification. London, 2004.
Wawro, Geoffrey. The Austro-Prussian War: Austria's War with Prussia and Italy in 1866. Cambridge, U.K., 1996. The most detailed account, presented from an Austrian perspective.