Austro-Prussian War
The pretext for the conflict was found in the dispute between Prussia and Austria over the administration of Schleswig-Holstein, which the two of them had conquered from Denmark and agreed to jointly occupy at the end of the Second Schleswig War in 1864. When Austria brought the dispute before the German Diet and also decided to convene the Diet of Holstein, Prussia declared that the Gastein Convention had thereby been nullified and invaded Holstein. When the German Diet responded by voting for a partial mobilization against Prussia, Bismarck claimed that the German Confederation was ended. Crown Prince Frederick "was the only member of the Prussian Crown Council to uphold the rights of the Duke of Augustenburg and oppose the idea of a war with Austria which he described as "fratricide"". Although he supported unification and the restoration of the medieval empire, "Fritz could not accept that war was the right way to unite Germany."
Otto von Bismarck
The war lasted seven weeks; Germans called it a "Blitzkrieg" ("lightning war"), a term also used in 1939. Austria had a seemingly powerful army that was allied with most of the north German and all of the south German states. Nevertheless, Prussia won the decisive Battle of Königgrätz. The King and his generals wanted to push onward, conquer Bohemia and march to Vienna, but Bismarck, worried that Prussian military luck might change or that France might intervene on Austria's side, enlisted the help of the Crown Prince, who had opposed the war but had commanded one of the Prussian armies at Königgrätz, to dissuade his father after stormy meetings. Bismarck insisted on a "soft peace" with no annexations and no victory parades, so as to be able to quickly restore friendly relations with Austria.