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."
History of Austria
These acquisitions together with conquests in the Balkans gave Austria its greatest territorial extent to date. 1713 also saw the Pragmatic Sanction, designed to prevent any further division of the territory. But when Charles VI (Archduke 1711–1740) died and was succeeded by his daughter, Maria Theresa (1740–1780) Austria was perceived as weak, leading to the War of Austrian Succession (1740–1748) and the Seven Years' War (1756–1763). Subsequently, Austria lost Silesia to Prussia. Austria also lost prior conquests from the Ottomans except Banat of Temeswar and Syrmia in the Austro-Russian–Turkish War despite being allied with Russia.